110 lines
2.7 KiB
JavaScript
110 lines
2.7 KiB
JavaScript
/**
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* Copyright (c) 2013-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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*/
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'use strict';
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const babel = require('babel-core');
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const t = babel.types;
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const NAME = 'regenerator-runtime';
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const REGENERATOR_NOT_NEEDED = 'NOT_NEEDED';
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const REGENERATOR_NEEDED = 'NEEDED';
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const REGENERATOR_ALREADY_REQUIRED = 'ALREADY_REQUIRED';
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function flagState(state) {
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if (state !== REGENERATOR_ALREADY_REQUIRED) {
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state.regeneratorRequired = REGENERATOR_NEEDED;
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}
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}
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function checkRequire(node, state) {
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const method = node.callee.name;
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const args = node.arguments;
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if (
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method === 'require' &&
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t.isStringLiteral(args[0]) &&
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args[0].value.startsWith(NAME)
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) {
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state.regeneratorRequired = REGENERATOR_ALREADY_REQUIRED;
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}
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}
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function checkFunction(node, state) {
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// Method is neither a generator nor an async function; skip.
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if (!node.generator && !node.async) {
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return;
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}
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// This will only set the status to needed if it hasn't already been required.
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if (state.regeneratorRequired === REGENERATOR_NOT_NEEDED) {
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state.regeneratorRequired = REGENERATOR_NEEDED;
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}
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}
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const isGeneratorRequired = {
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CallExpression(path, state) {
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checkRequire(path.node, state);
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},
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FunctionDeclaration(path, state) {
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checkFunction(path.node, state);
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},
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ClassMethod(path, state) {
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checkFunction(path.node, state);
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},
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ArrowFunctionExpression(path, state) {
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checkFunction(path.node, state);
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},
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FunctionExpression(path, state) {
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checkFunction(path.node, state);
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},
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YieldExpression(path, state) {
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flagState(state);
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},
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AwaitExpression(path, state) {
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flagState(state);
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},
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};
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/**
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* Adds a "const regeneratorRuntime = require('regenerator-runtime') to each
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* file that does not include regenerator-runtime, but requires it because it
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* contains async/await or generators.
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*/
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module.exports = function() {
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return {
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visitor: {
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Program(path, state) {
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state.regeneratorRequired = REGENERATOR_NOT_NEEDED;
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path.traverse(isGeneratorRequired, state);
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if (state.regeneratorRequired === REGENERATOR_NEEDED) {
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path.node.body.unshift(
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t.variableDeclaration('const', [
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t.variableDeclarator(
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t.identifier('regeneratorRuntime'),
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t.callExpression(t.identifier('require'), [
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t.stringLiteral(NAME),
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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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};
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