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/*
MIT License http://www.opensource.org/licenses/mit-license.php
Author Tobias Koppers @sokra
*/
"use strict";
const DynamicExports = require("./DynamicExports");
const HarmonyCompatibilityDependency = require("./HarmonyCompatibilityDependency");
const HarmonyExports = require("./HarmonyExports");
module.exports = class HarmonyDetectionParserPlugin {
constructor(options) {
const { topLevelAwait = false } = options || {};
this.topLevelAwait = topLevelAwait;
}
apply(parser) {
parser.hooks.program.tap("HarmonyDetectionParserPlugin", ast => {
const isStrictHarmony = parser.state.module.type === "javascript/esm";
const isHarmony =
isStrictHarmony ||
ast.body.some(
statement =>
statement.type === "ImportDeclaration" ||
statement.type === "ExportDefaultDeclaration" ||
statement.type === "ExportNamedDeclaration" ||
statement.type === "ExportAllDeclaration"
);
if (isHarmony) {
const module = parser.state.module;
const compatDep = new HarmonyCompatibilityDependency();
compatDep.loc = {
start: {
line: -1,
column: 0
},
end: {
line: -1,
column: 0
},
index: -3
};
module.addPresentationalDependency(compatDep);
DynamicExports.bailout(parser.state);
HarmonyExports.enable(parser.state, isStrictHarmony);
parser.scope.isStrict = true;
}
});
parser.hooks.topLevelAwait.tap("HarmonyDetectionParserPlugin", () => {
const module = parser.state.module;
if (!this.topLevelAwait) {
throw new Error(
"The top-level-await experiment is not enabled (set experiments.topLevelAwait: true to enabled it)"
);
}
if (!HarmonyExports.isEnabled(parser.state)) {
throw new Error(
"Top-level-await is only supported in EcmaScript Modules"
);
}
module.buildMeta.async = true;
});
const skipInHarmony = () => {
if (HarmonyExports.isEnabled(parser.state)) {
return true;
}
};
const nullInHarmony = () => {
if (HarmonyExports.isEnabled(parser.state)) {
return null;
}
};
const nonHarmonyIdentifiers = ["define", "exports"];
for (const identifier of nonHarmonyIdentifiers) {
parser.hooks.evaluateTypeof
.for(identifier)
.tap("HarmonyDetectionParserPlugin", nullInHarmony);
parser.hooks.typeof
.for(identifier)
.tap("HarmonyDetectionParserPlugin", skipInHarmony);
parser.hooks.evaluate
.for(identifier)
.tap("HarmonyDetectionParserPlugin", nullInHarmony);
parser.hooks.expression
.for(identifier)
.tap("HarmonyDetectionParserPlugin", skipInHarmony);
parser.hooks.call
.for(identifier)
.tap("HarmonyDetectionParserPlugin", skipInHarmony);
}
}
};