280 lines
9.8 KiB
Plaintext
280 lines
9.8 KiB
Plaintext
|
|
import {TokenType as tt} from "../parser/tokenizer/types";
|
|
|
|
import isIdentifier from "../util/isIdentifier";
|
|
|
|
import Transformer from "./Transformer";
|
|
|
|
export default class TypeScriptTransformer extends Transformer {
|
|
constructor(
|
|
rootTransformer,
|
|
tokens,
|
|
isImportsTransformEnabled,
|
|
) {
|
|
super();this.rootTransformer = rootTransformer;this.tokens = tokens;this.isImportsTransformEnabled = isImportsTransformEnabled;;
|
|
}
|
|
|
|
process() {
|
|
if (
|
|
this.rootTransformer.processPossibleArrowParamEnd() ||
|
|
this.rootTransformer.processPossibleAsyncArrowWithTypeParams() ||
|
|
this.rootTransformer.processPossibleTypeRange()
|
|
) {
|
|
return true;
|
|
}
|
|
if (
|
|
this.tokens.matches1(tt._public) ||
|
|
this.tokens.matches1(tt._protected) ||
|
|
this.tokens.matches1(tt._private) ||
|
|
this.tokens.matches1(tt._abstract) ||
|
|
this.tokens.matches1(tt._readonly) ||
|
|
this.tokens.matches1(tt._override) ||
|
|
this.tokens.matches1(tt.nonNullAssertion)
|
|
) {
|
|
this.tokens.removeInitialToken();
|
|
return true;
|
|
}
|
|
if (this.tokens.matches1(tt._enum) || this.tokens.matches2(tt._const, tt._enum)) {
|
|
this.processEnum();
|
|
return true;
|
|
}
|
|
if (
|
|
this.tokens.matches2(tt._export, tt._enum) ||
|
|
this.tokens.matches3(tt._export, tt._const, tt._enum)
|
|
) {
|
|
this.processEnum(true);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
processEnum(isExport = false) {
|
|
// We might have "export const enum", so just remove all relevant tokens.
|
|
this.tokens.removeInitialToken();
|
|
while (this.tokens.matches1(tt._const) || this.tokens.matches1(tt._enum)) {
|
|
this.tokens.removeToken();
|
|
}
|
|
const enumName = this.tokens.identifierName();
|
|
this.tokens.removeToken();
|
|
if (isExport && !this.isImportsTransformEnabled) {
|
|
this.tokens.appendCode("export ");
|
|
}
|
|
this.tokens.appendCode(`var ${enumName}; (function (${enumName})`);
|
|
this.tokens.copyExpectedToken(tt.braceL);
|
|
this.processEnumBody(enumName);
|
|
this.tokens.copyExpectedToken(tt.braceR);
|
|
if (isExport && this.isImportsTransformEnabled) {
|
|
this.tokens.appendCode(`)(${enumName} || (exports.${enumName} = ${enumName} = {}));`);
|
|
} else {
|
|
this.tokens.appendCode(`)(${enumName} || (${enumName} = {}));`);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Transform an enum into equivalent JS. This has complexity in a few places:
|
|
* - TS allows string enums, numeric enums, and a mix of the two styles within an enum.
|
|
* - Enum keys are allowed to be referenced in later enum values.
|
|
* - Enum keys are allowed to be strings.
|
|
* - When enum values are omitted, they should follow an auto-increment behavior.
|
|
*/
|
|
processEnumBody(enumName) {
|
|
// Code that can be used to reference the previous enum member, or null if this is the first
|
|
// enum member.
|
|
let previousValueCode = null;
|
|
while (true) {
|
|
if (this.tokens.matches1(tt.braceR)) {
|
|
break;
|
|
}
|
|
const {nameStringCode, variableName} = this.extractEnumKeyInfo(this.tokens.currentToken());
|
|
this.tokens.removeInitialToken();
|
|
|
|
if (
|
|
this.tokens.matches3(tt.eq, tt.string, tt.comma) ||
|
|
this.tokens.matches3(tt.eq, tt.string, tt.braceR)
|
|
) {
|
|
this.processStringLiteralEnumMember(enumName, nameStringCode, variableName);
|
|
} else if (this.tokens.matches1(tt.eq)) {
|
|
this.processExplicitValueEnumMember(enumName, nameStringCode, variableName);
|
|
} else {
|
|
this.processImplicitValueEnumMember(
|
|
enumName,
|
|
nameStringCode,
|
|
variableName,
|
|
previousValueCode,
|
|
);
|
|
}
|
|
if (this.tokens.matches1(tt.comma)) {
|
|
this.tokens.removeToken();
|
|
}
|
|
|
|
if (variableName != null) {
|
|
previousValueCode = variableName;
|
|
} else {
|
|
previousValueCode = `${enumName}[${nameStringCode}]`;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Detect name information about this enum key, which will be used to determine which code to emit
|
|
* and whether we should declare a variable as part of this declaration.
|
|
*
|
|
* Some cases to keep in mind:
|
|
* - Enum keys can be implicitly referenced later, e.g. `X = 1, Y = X`. In Sucrase, we implement
|
|
* this by declaring a variable `X` so that later expressions can use it.
|
|
* - In addition to the usual identifier key syntax, enum keys are allowed to be string literals,
|
|
* e.g. `"hello world" = 3,`. Template literal syntax is NOT allowed.
|
|
* - Even if the enum key is defined as a string literal, it may still be referenced by identifier
|
|
* later, e.g. `"X" = 1, Y = X`. That means that we need to detect whether or not a string
|
|
* literal is identifier-like and emit a variable if so, even if the declaration did not use an
|
|
* identifier.
|
|
* - Reserved keywords like `break` are valid enum keys, but are not valid to be referenced later
|
|
* and would be a syntax error if we emitted a variable, so we need to skip the variable
|
|
* declaration in those cases.
|
|
*
|
|
* The variableName return value captures these nuances: if non-null, we can and must emit a
|
|
* variable declaration, and if null, we can't and shouldn't.
|
|
*/
|
|
extractEnumKeyInfo(nameToken) {
|
|
if (nameToken.type === tt.name) {
|
|
const name = this.tokens.identifierNameForToken(nameToken);
|
|
return {
|
|
nameStringCode: `"${name}"`,
|
|
variableName: isIdentifier(name) ? name : null,
|
|
};
|
|
} else if (nameToken.type === tt.string) {
|
|
const name = this.tokens.stringValueForToken(nameToken);
|
|
return {
|
|
nameStringCode: this.tokens.code.slice(nameToken.start, nameToken.end),
|
|
variableName: isIdentifier(name) ? name : null,
|
|
};
|
|
} else {
|
|
throw new Error("Expected name or string at beginning of enum element.");
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Handle an enum member where the RHS is just a string literal (not omitted, not a number, and
|
|
* not a complex expression). This is the typical form for TS string enums, and in this case, we
|
|
* do *not* create a reverse mapping.
|
|
*
|
|
* This is called after deleting the key token, when the token processor is at the equals sign.
|
|
*
|
|
* Example 1:
|
|
* someKey = "some value"
|
|
* ->
|
|
* const someKey = "some value"; MyEnum["someKey"] = someKey;
|
|
*
|
|
* Example 2:
|
|
* "some key" = "some value"
|
|
* ->
|
|
* MyEnum["some key"] = "some value";
|
|
*/
|
|
processStringLiteralEnumMember(
|
|
enumName,
|
|
nameStringCode,
|
|
variableName,
|
|
) {
|
|
if (variableName != null) {
|
|
this.tokens.appendCode(`const ${variableName}`);
|
|
// =
|
|
this.tokens.copyToken();
|
|
// value string
|
|
this.tokens.copyToken();
|
|
this.tokens.appendCode(`; ${enumName}[${nameStringCode}] = ${variableName};`);
|
|
} else {
|
|
this.tokens.appendCode(`${enumName}[${nameStringCode}]`);
|
|
// =
|
|
this.tokens.copyToken();
|
|
// value string
|
|
this.tokens.copyToken();
|
|
this.tokens.appendCode(";");
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Handle an enum member initialized with an expression on the right-hand side (other than a
|
|
* string literal). In these cases, we should transform the expression and emit code that sets up
|
|
* a reverse mapping.
|
|
*
|
|
* The TypeScript implementation of this operation distinguishes between expressions that can be
|
|
* "constant folded" at compile time (i.e. consist of number literals and simple math operations
|
|
* on those numbers) and ones that are dynamic. For constant expressions, it emits the resolved
|
|
* numeric value, and auto-incrementing is only allowed in that case. Evaluating expressions at
|
|
* compile time would add significant complexity to Sucrase, so Sucrase instead leaves the
|
|
* expression as-is, and will later emit something like `MyEnum["previousKey"] + 1` to implement
|
|
* auto-incrementing.
|
|
*
|
|
* This is called after deleting the key token, when the token processor is at the equals sign.
|
|
*
|
|
* Example 1:
|
|
* someKey = 1 + 1
|
|
* ->
|
|
* const someKey = 1 + 1; MyEnum[MyEnum["someKey"] = someKey] = "someKey";
|
|
*
|
|
* Example 2:
|
|
* "some key" = 1 + 1
|
|
* ->
|
|
* MyEnum[MyEnum["some key"] = 1 + 1] = "some key";
|
|
*/
|
|
processExplicitValueEnumMember(
|
|
enumName,
|
|
nameStringCode,
|
|
variableName,
|
|
) {
|
|
const rhsEndIndex = this.tokens.currentToken().rhsEndIndex;
|
|
if (rhsEndIndex == null) {
|
|
throw new Error("Expected rhsEndIndex on enum assign.");
|
|
}
|
|
|
|
if (variableName != null) {
|
|
this.tokens.appendCode(`const ${variableName}`);
|
|
this.tokens.copyToken();
|
|
while (this.tokens.currentIndex() < rhsEndIndex) {
|
|
this.rootTransformer.processToken();
|
|
}
|
|
this.tokens.appendCode(
|
|
`; ${enumName}[${enumName}[${nameStringCode}] = ${variableName}] = ${nameStringCode};`,
|
|
);
|
|
} else {
|
|
this.tokens.appendCode(`${enumName}[${enumName}[${nameStringCode}]`);
|
|
this.tokens.copyToken();
|
|
while (this.tokens.currentIndex() < rhsEndIndex) {
|
|
this.rootTransformer.processToken();
|
|
}
|
|
this.tokens.appendCode(`] = ${nameStringCode};`);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Handle an enum member with no right-hand side expression. In this case, the value is the
|
|
* previous value plus 1, or 0 if there was no previous value. We should also always emit a
|
|
* reverse mapping.
|
|
*
|
|
* Example 1:
|
|
* someKey2
|
|
* ->
|
|
* const someKey2 = someKey1 + 1; MyEnum[MyEnum["someKey2"] = someKey2] = "someKey2";
|
|
*
|
|
* Example 2:
|
|
* "some key 2"
|
|
* ->
|
|
* MyEnum[MyEnum["some key 2"] = someKey1 + 1] = "some key 2";
|
|
*/
|
|
processImplicitValueEnumMember(
|
|
enumName,
|
|
nameStringCode,
|
|
variableName,
|
|
previousValueCode,
|
|
) {
|
|
let valueCode = previousValueCode != null ? `${previousValueCode} + 1` : "0";
|
|
if (variableName != null) {
|
|
this.tokens.appendCode(`const ${variableName} = ${valueCode}; `);
|
|
valueCode = variableName;
|
|
}
|
|
this.tokens.appendCode(
|
|
`${enumName}[${enumName}[${nameStringCode}] = ${valueCode}] = ${nameStringCode};`,
|
|
);
|
|
}
|
|
}
|