webpack/lib/UseStrictPlugin.js

36 lines
1.1 KiB
JavaScript

/*
MIT License http://www.opensource.org/licenses/mit-license.php
Author Tobias Koppers @sokra
*/
"use strict"
const ConstDependency = require("./dependencies/ConstDependency");
class UseStrictPlugin {
apply(compiler) {
compiler.plugin("compilation", (compilation, params) => {
params.normalModuleFactory.plugin("parser", (parser) => {
let parserInstance = parser;
parser.plugin("program", (ast) => {
let firstNode = ast.body[0];
let dep;
if(firstNode &&
firstNode.type === "ExpressionStatement" &&
firstNode.expression.type === "Literal" &&
firstNode.expression.value === "use strict") {
// Remove "use strict" expression. It will be added later by the renderer again.
// This is necessary in order to not break the strict mode when webpack prepends code.
// @see https://github.com/webpack/webpack/issues/1970
dep = new ConstDependency("", firstNode.range);
dep.loc = firstNode.loc;
parserInstance.state.current.addDependency(dep);
parserInstance.state.module.strict = true;
}
});
})
})
}
}
module.exports = UseStrictPlugin;