346 lines
16 KiB
Plaintext
346 lines
16 KiB
Plaintext
"use strict";
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var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
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if (k2 === undefined) k2 = k;
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var desc = Object.getOwnPropertyDescriptor(m, k);
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if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
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desc = { enumerable: true, get: function() { return m[k]; } };
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}
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Object.defineProperty(o, k2, desc);
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}) : (function(o, m, k, k2) {
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if (k2 === undefined) k2 = k;
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o[k2] = m[k];
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}));
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var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
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Object.defineProperty(o, "default", { enumerable: true, value: v });
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}) : function(o, v) {
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o["default"] = v;
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});
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var __importStar = (this && this.__importStar) || function (mod) {
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if (mod && mod.__esModule) return mod;
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var result = {};
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if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
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__setModuleDefault(result, mod);
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return result;
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};
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Object.defineProperty(exports, "__esModule", { value: true });
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const utils_1 = require("@typescript-eslint/utils");
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const tsutils = __importStar(require("ts-api-utils"));
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const ts = __importStar(require("typescript"));
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const util_1 = require("../util");
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exports.default = (0, util_1.createRule)({
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name: 'prefer-nullish-coalescing',
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meta: {
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type: 'suggestion',
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docs: {
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description: 'Enforce using the nullish coalescing operator instead of logical assignments or chaining',
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recommended: 'stylistic',
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requiresTypeChecking: true,
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},
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hasSuggestions: true,
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messages: {
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preferNullishOverOr: 'Prefer using nullish coalescing operator (`??`) instead of a logical or (`||`), as it is a safer operator.',
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preferNullishOverTernary: 'Prefer using nullish coalescing operator (`??`) instead of a ternary expression, as it is simpler to read.',
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suggestNullish: 'Fix to nullish coalescing operator (`??`).',
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noStrictNullCheck: 'This rule requires the `strictNullChecks` compiler option to be turned on to function correctly.',
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},
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schema: [
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{
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type: 'object',
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properties: {
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allowRuleToRunWithoutStrictNullChecksIKnowWhatIAmDoing: {
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type: 'boolean',
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},
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ignoreConditionalTests: {
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type: 'boolean',
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},
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ignoreMixedLogicalExpressions: {
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type: 'boolean',
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},
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ignorePrimitives: {
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oneOf: [
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{
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type: 'object',
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properties: {
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bigint: { type: 'boolean' },
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boolean: { type: 'boolean' },
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number: { type: 'boolean' },
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string: { type: 'boolean' },
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},
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},
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{
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type: 'boolean',
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enum: [true],
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},
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],
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},
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ignoreTernaryTests: {
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type: 'boolean',
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},
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},
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additionalProperties: false,
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},
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],
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},
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defaultOptions: [
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{
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allowRuleToRunWithoutStrictNullChecksIKnowWhatIAmDoing: false,
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ignoreConditionalTests: false,
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ignoreTernaryTests: false,
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ignoreMixedLogicalExpressions: false,
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ignorePrimitives: {
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bigint: false,
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boolean: false,
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number: false,
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string: false,
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},
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},
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],
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create(context, [{ allowRuleToRunWithoutStrictNullChecksIKnowWhatIAmDoing, ignoreConditionalTests, ignoreMixedLogicalExpressions, ignorePrimitives, ignoreTernaryTests, },]) {
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const parserServices = (0, util_1.getParserServices)(context);
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const compilerOptions = parserServices.program.getCompilerOptions();
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const checker = parserServices.program.getTypeChecker();
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const isStrictNullChecks = tsutils.isStrictCompilerOptionEnabled(compilerOptions, 'strictNullChecks');
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if (!isStrictNullChecks &&
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allowRuleToRunWithoutStrictNullChecksIKnowWhatIAmDoing !== true) {
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context.report({
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loc: {
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start: { line: 0, column: 0 },
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end: { line: 0, column: 0 },
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},
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messageId: 'noStrictNullCheck',
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});
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}
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return {
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ConditionalExpression(node) {
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if (ignoreTernaryTests) {
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return;
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}
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let operator;
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let nodesInsideTestExpression = [];
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if (node.test.type === utils_1.AST_NODE_TYPES.BinaryExpression) {
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nodesInsideTestExpression = [node.test.left, node.test.right];
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if (node.test.operator === '==' ||
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node.test.operator === '!=' ||
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node.test.operator === '===' ||
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node.test.operator === '!==') {
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operator = node.test.operator;
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}
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}
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else if (node.test.type === utils_1.AST_NODE_TYPES.LogicalExpression &&
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node.test.left.type === utils_1.AST_NODE_TYPES.BinaryExpression &&
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node.test.right.type === utils_1.AST_NODE_TYPES.BinaryExpression) {
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nodesInsideTestExpression = [
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node.test.left.left,
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node.test.left.right,
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node.test.right.left,
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node.test.right.right,
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];
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if (node.test.operator === '||') {
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if (node.test.left.operator === '===' &&
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node.test.right.operator === '===') {
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operator = '===';
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}
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else if (((node.test.left.operator === '===' ||
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node.test.right.operator === '===') &&
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(node.test.left.operator === '==' ||
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node.test.right.operator === '==')) ||
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(node.test.left.operator === '==' &&
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node.test.right.operator === '==')) {
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operator = '==';
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}
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}
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else if (node.test.operator === '&&') {
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if (node.test.left.operator === '!==' &&
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node.test.right.operator === '!==') {
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operator = '!==';
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}
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else if (((node.test.left.operator === '!==' ||
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node.test.right.operator === '!==') &&
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(node.test.left.operator === '!=' ||
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node.test.right.operator === '!=')) ||
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(node.test.left.operator === '!=' &&
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node.test.right.operator === '!=')) {
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operator = '!=';
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}
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}
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}
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if (!operator) {
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return;
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}
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let identifier;
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let hasUndefinedCheck = false;
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let hasNullCheck = false;
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// we check that the test only contains null, undefined and the identifier
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for (const testNode of nodesInsideTestExpression) {
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if ((0, util_1.isNullLiteral)(testNode)) {
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hasNullCheck = true;
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}
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else if ((0, util_1.isUndefinedIdentifier)(testNode)) {
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hasUndefinedCheck = true;
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}
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else if ((operator === '!==' || operator === '!=') &&
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(0, util_1.isNodeEqual)(testNode, node.consequent)) {
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identifier = testNode;
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}
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else if ((operator === '===' || operator === '==') &&
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(0, util_1.isNodeEqual)(testNode, node.alternate)) {
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identifier = testNode;
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}
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else {
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return;
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}
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}
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if (!identifier) {
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return;
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}
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const isFixable = (() => {
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// it is fixable if we check for both null and undefined, or not if neither
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if (hasUndefinedCheck === hasNullCheck) {
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return hasUndefinedCheck;
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}
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// it is fixable if we loosely check for either null or undefined
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if (operator === '==' || operator === '!=') {
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return true;
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}
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const tsNode = parserServices.esTreeNodeToTSNodeMap.get(identifier);
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const type = checker.getTypeAtLocation(tsNode);
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const flags = (0, util_1.getTypeFlags)(type);
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if (flags & (ts.TypeFlags.Any | ts.TypeFlags.Unknown)) {
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return false;
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}
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const hasNullType = (flags & ts.TypeFlags.Null) !== 0;
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// it is fixable if we check for undefined and the type is not nullable
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if (hasUndefinedCheck && !hasNullType) {
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return true;
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}
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const hasUndefinedType = (flags & ts.TypeFlags.Undefined) !== 0;
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// it is fixable if we check for null and the type can't be undefined
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return hasNullCheck && !hasUndefinedType;
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})();
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if (isFixable) {
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context.report({
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node,
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messageId: 'preferNullishOverTernary',
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suggest: [
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{
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messageId: 'suggestNullish',
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fix(fixer) {
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const [left, right] = operator === '===' || operator === '=='
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? [node.alternate, node.consequent]
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: [node.consequent, node.alternate];
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return fixer.replaceText(node, `${context.sourceCode.text.slice(left.range[0], left.range[1])} ?? ${context.sourceCode.text.slice(right.range[0], right.range[1])}`);
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},
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},
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],
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});
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}
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},
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'LogicalExpression[operator = "||"]'(node) {
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const tsNode = parserServices.esTreeNodeToTSNodeMap.get(node);
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const type = checker.getTypeAtLocation(tsNode.left);
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if (!(0, util_1.isTypeFlagSet)(type, ts.TypeFlags.Null | ts.TypeFlags.Undefined)) {
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return;
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}
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if (ignoreConditionalTests === true && isConditionalTest(node)) {
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return;
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}
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const isMixedLogical = isMixedLogicalExpression(node);
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if (ignoreMixedLogicalExpressions === true && isMixedLogical) {
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return;
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}
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const ignorableFlags = [
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(ignorePrimitives === true || ignorePrimitives.bigint) &&
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ts.TypeFlags.BigInt,
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(ignorePrimitives === true || ignorePrimitives.boolean) &&
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ts.TypeFlags.BooleanLiteral,
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(ignorePrimitives === true || ignorePrimitives.number) &&
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ts.TypeFlags.Number,
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(ignorePrimitives === true || ignorePrimitives.string) &&
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ts.TypeFlags.String,
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]
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.filter((flag) => typeof flag === 'number')
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.reduce((previous, flag) => previous | flag, 0);
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if (type.flags !== ts.TypeFlags.Null &&
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type.flags !== ts.TypeFlags.Undefined &&
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type.types.some(t => tsutils.isTypeFlagSet(t, ignorableFlags))) {
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return;
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}
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const barBarOperator = (0, util_1.nullThrows)(context.sourceCode.getTokenAfter(node.left, token => token.type === utils_1.AST_TOKEN_TYPES.Punctuator &&
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token.value === node.operator), util_1.NullThrowsReasons.MissingToken('operator', node.type));
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function* fix(fixer) {
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if ((0, util_1.isLogicalOrOperator)(node.parent)) {
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// '&&' and '??' operations cannot be mixed without parentheses (e.g. a && b ?? c)
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if (node.left.type === utils_1.AST_NODE_TYPES.LogicalExpression &&
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!(0, util_1.isLogicalOrOperator)(node.left.left)) {
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yield fixer.insertTextBefore(node.left.right, '(');
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}
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else {
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yield fixer.insertTextBefore(node.left, '(');
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}
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yield fixer.insertTextAfter(node.right, ')');
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}
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yield fixer.replaceText(barBarOperator, '??');
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}
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context.report({
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node: barBarOperator,
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messageId: 'preferNullishOverOr',
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suggest: [
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{
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messageId: 'suggestNullish',
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fix,
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},
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],
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});
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},
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};
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},
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});
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function isConditionalTest(node) {
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const parents = new Set([node]);
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let current = node.parent;
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while (current) {
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parents.add(current);
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if ((current.type === utils_1.AST_NODE_TYPES.ConditionalExpression ||
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current.type === utils_1.AST_NODE_TYPES.DoWhileStatement ||
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current.type === utils_1.AST_NODE_TYPES.IfStatement ||
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current.type === utils_1.AST_NODE_TYPES.ForStatement ||
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current.type === utils_1.AST_NODE_TYPES.WhileStatement) &&
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parents.has(current.test)) {
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return true;
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}
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if ([
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utils_1.AST_NODE_TYPES.ArrowFunctionExpression,
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utils_1.AST_NODE_TYPES.FunctionExpression,
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].includes(current.type)) {
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/**
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* This is a weird situation like:
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* `if (() => a || b) {}`
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* `if (function () { return a || b }) {}`
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*/
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return false;
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}
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current = current.parent;
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}
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return false;
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}
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function isMixedLogicalExpression(node) {
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const seen = new Set();
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const queue = [node.parent, node.left, node.right];
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for (const current of queue) {
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if (seen.has(current)) {
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continue;
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}
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seen.add(current);
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if (current.type === utils_1.AST_NODE_TYPES.LogicalExpression) {
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if (current.operator === '&&') {
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return true;
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}
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else if (current.operator === '||') {
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// check the pieces of the node to catch cases like `a || b || c && d`
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queue.push(current.parent, current.left, current.right);
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}
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}
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}
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return false;
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}
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//# sourceMappingURL=prefer-nullish-coalescing.js.map |