74 lines
3.6 KiB
Plaintext
74 lines
3.6 KiB
Plaintext
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"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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const scope_manager_1 = require("@typescript-eslint/scope-manager");
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const utils_1 = require("@typescript-eslint/utils");
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const util_1 = require("../util");
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function hasAssignmentBeforeNode(variable, node) {
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return (variable.references.some(ref => ref.isWrite() && ref.identifier.range[1] < node.range[1]) ||
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variable.defs.some(def => isDefinitionWithAssignment(def) && def.node.range[1] < node.range[1]));
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}
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function isDefinitionWithAssignment(definition) {
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if (definition.type !== scope_manager_1.DefinitionType.Variable) {
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return false;
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}
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const variableDeclarator = definition.node;
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return variableDeclarator.definite || variableDeclarator.init != null;
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}
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exports.default = (0, util_1.createRule)({
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name: 'no-non-null-asserted-nullish-coalescing',
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meta: {
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type: 'problem',
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docs: {
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description: 'Disallow non-null assertions in the left operand of a nullish coalescing operator',
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recommended: 'strict',
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},
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messages: {
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noNonNullAssertedNullishCoalescing: 'The nullish coalescing operator is designed to handle undefined and null - using a non-null assertion is not needed.',
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suggestRemovingNonNull: 'Remove the non-null assertion.',
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},
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schema: [],
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hasSuggestions: true,
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},
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defaultOptions: [],
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create(context) {
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return {
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'LogicalExpression[operator = "??"] > TSNonNullExpression.left'(node) {
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if (node.expression.type === utils_1.TSESTree.AST_NODE_TYPES.Identifier) {
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const scope = context.sourceCode.getScope(node);
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const identifier = node.expression;
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const variable = utils_1.ASTUtils.findVariable(scope, identifier.name);
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if (variable && !hasAssignmentBeforeNode(variable, node)) {
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return;
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}
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}
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context.report({
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node,
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messageId: 'noNonNullAssertedNullishCoalescing',
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/*
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Use a suggestion instead of a fixer, because this can break type checks.
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The resulting type of the nullish coalesce is only influenced by the right operand if the left operand can be `null` or `undefined`.
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After removing the non-null assertion the type of the left operand might contain `null` or `undefined` and then the type of the right operand
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might change the resulting type of the nullish coalesce.
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See the following example:
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function test(x?: string): string {
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const bar = x! ?? false; // type analysis reports `bar` has type `string`
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// x ?? false; // type analysis reports `bar` has type `string | false`
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return bar;
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}
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*/
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suggest: [
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{
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messageId: 'suggestRemovingNonNull',
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fix(fixer) {
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const exclamationMark = (0, util_1.nullThrows)(context.sourceCode.getLastToken(node, utils_1.ASTUtils.isNonNullAssertionPunctuator), util_1.NullThrowsReasons.MissingToken('!', 'Non-null Assertion'));
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return fixer.remove(exclamationMark);
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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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});
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//# sourceMappingURL=no-non-null-asserted-nullish-coalescing.js.map
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