147 lines
3.2 KiB
JavaScript
147 lines
3.2 KiB
JavaScript
'use strict';
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const {
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isIdentifierName,
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isStrictReservedWord,
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isKeyword,
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} = require('@babel/helper-validator-identifier');
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const resolveVariableName = require('./resolve-variable-name.js');
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const getReferences = require('./get-references.js');
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// https://github.com/microsoft/TypeScript/issues/2536#issuecomment-87194347
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const typescriptReservedWords = new Set([
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'break',
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'case',
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'catch',
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'class',
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'const',
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'continue',
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'debugger',
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'default',
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'delete',
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'do',
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'else',
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'enum',
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'export',
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'extends',
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'false',
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'finally',
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'for',
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'function',
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'if',
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'import',
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'in',
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'instanceof',
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'new',
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'null',
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'return',
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'super',
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'switch',
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'this',
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'throw',
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'true',
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'try',
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'typeof',
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'var',
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'void',
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'while',
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'with',
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'as',
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'implements',
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'interface',
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'let',
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'package',
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'private',
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'protected',
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'public',
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'static',
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'yield',
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'any',
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'boolean',
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'constructor',
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'declare',
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'get',
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'module',
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'require',
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'number',
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'set',
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'string',
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'symbol',
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'type',
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'from',
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'of',
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]);
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// Copied from https://github.com/babel/babel/blob/fce35af69101c6b316557e28abf60bdbf77d6a36/packages/babel-types/src/validators/isValidIdentifier.ts#L7
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// Use this function instead of `require('@babel/types').isIdentifier`, since `@babel/helper-validator-identifier` package is much smaller
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const isValidIdentifier = name =>
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typeof name === 'string'
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&& !isKeyword(name)
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&& !isStrictReservedWord(name, true)
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&& isIdentifierName(name)
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&& name !== 'arguments'
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&& !typescriptReservedWords.has(name);
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/*
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Unresolved reference is probably from the global scope. We should avoid using that name.
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For example, like `foo` and `bar` below.
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```
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function unicorn() {
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return foo;
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}
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function unicorn() {
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return function() {
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return bar;
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};
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}
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```
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*/
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const isUnresolvedName = (name, scope) =>
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getReferences(scope).some(({identifier, resolved}) => identifier?.name === name && !resolved);
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const isSafeName = (name, scopes) =>
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!scopes.some(scope => resolveVariableName(name, scope) || isUnresolvedName(name, scope));
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const alwaysTrue = () => true;
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/**
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Rule-specific name check function.
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@callback isSafe
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@param {string} name - The generated candidate name.
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@param {Scope[]} scopes - The same list of scopes you pass to `avoidCapture`.
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@returns {boolean} - `true` if the `name` is ok.
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*/
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/**
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Generates a unique name prefixed with `name` such that:
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- it is not defined in any of the `scopes`,
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- it is not a reserved word,
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- it is not `arguments` in strict scopes (where `arguments` is not allowed),
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- it does not collide with the actual `arguments` (which is always defined in function scopes).
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Useful when you want to rename a variable (or create a new variable) while being sure not to shadow any other variables in the code.
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@param {string} name - The desired name for a new variable.
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@param {Scope[]} scopes - The list of scopes the new variable will be referenced in.
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@param {isSafe} [isSafe] - Rule-specific name check function.
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@returns {string} - Either `name` as is, or a string like `${name}_` suffixed with underscores to make the name unique.
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*/
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module.exports = (name, scopes, isSafe = alwaysTrue) => {
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if (!isValidIdentifier(name)) {
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name += '_';
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if (!isValidIdentifier(name)) {
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return;
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}
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}
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while (!isSafeName(name, scopes) || !isSafe(name, scopes)) {
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name += '_';
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}
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return name;
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};
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