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"use strict";
// TODO: Use https://www.npmjs.com/package/pirates here?
var Module = require("module"),
fs = require("fs"),
eslint = require("eslint"),
coffee;
var moduleWrapper0 = Module.wrapper[0],
moduleWrapper1 = Module.wrapper[1],
originalExtensions = {},
linter = new eslint.Linter(),
eslintOptions = {
env: {
es6: true,
},
parserOptions: {
ecmaVersion: 6,
ecmaFeatures: {
globalReturn: true,
jsx: true,
experimentalObjectRestSpread: true
},
},
rules: {
"no-const-assign": 2
}
},
// The following regular expression is used to replace const declarations with let.
// This regex replacement is not 100% safe because transforming JavaScript requires an actual parser.
// However, parsing (e.g. via babel) comes with its own problems because now the parser needs to
// be aware of syntax extensions which might not be supported by the parser, but the underlying
// JavaScript engine. In fact, rewire used to have babel in place here but required an extra
// transform for the object spread operator (check out commit d9a81c0cdacf6995b24d205b4a2068adbd8b34ff
// or see https://github.com/jhnns/rewire/pull/128). It was also notable slower
// (see https://github.com/jhnns/rewire/issues/132).
// There is another issue: replacing const with let is not safe because of their different behavior.
// That's why we also have ESLint in place which tries to identify this error case.
// There is one edge case though: when a new syntax is used *and* a const re-assignment happens,
// rewire would compile happily in this situation but the actual code wouldn't work.
// However, since most projects have a seperate linting step which catches these const re-assignment
// errors anyway, it's probably still a reasonable trade-off.
// Test the regular expresssion at https://regex101.com/r/dvnZPv/2 and also check out testLib/constModule.js.
matchConst = /(^|\s|\}|;)const(\/\*|\s|{)/gm,
nodeRequire,
currentModule;
function load(targetModule) {
nodeRequire = targetModule.require;
targetModule.require = requireProxy;
currentModule = targetModule;
registerExtensions();
targetModule.load(targetModule.id);
// This is only necessary if nothing has been required within the module
reset();
}
function reset() {
Module.wrapper[0] = moduleWrapper0;
Module.wrapper[1] = moduleWrapper1;
}
function inject(prelude, appendix) {
Module.wrapper[0] = moduleWrapper0 + prelude;
Module.wrapper[1] = appendix + moduleWrapper1;
}
/**
* Proxies the first require call in order to draw back all changes to the Module.wrapper.
* Thus our changes don't influence other modules
*
* @param {!String} path
*/
function requireProxy(path) {
reset();
currentModule.require = nodeRequire;
return nodeRequire.call(currentModule, path); // node's require only works when "this" points to the module
}
function registerExtensions() {
var originalJsExtension = require.extensions[".js"];
var originalCoffeeExtension = require.extensions[".coffee"];
if (originalJsExtension) {
originalExtensions.js = originalJsExtension;
}
if (originalCoffeeExtension) {
originalExtensions.coffee = originalCoffeeExtension;
}
require.extensions[".js"] = jsExtension;
require.extensions[".coffee"] = coffeeExtension;
}
function restoreExtensions() {
if ("js" in originalExtensions) {
require.extensions[".js"] = originalExtensions.js;
}
if ("coffee" in originalExtensions) {
require.extensions[".coffee"] = originalExtensions.coffee;
}
}
function isNoConstAssignMessage(message) {
return message.ruleId === "no-const-assign";
}
function jsExtension(module, filename) {
var _compile = module._compile;
module._compile = function (content, filename) {
var noConstAssignMessage = linter.verify(content, eslintOptions).find(isNoConstAssignMessage);
var line;
var column;
if (noConstAssignMessage !== undefined) {
line = noConstAssignMessage.line;
column = noConstAssignMessage.column;
throw new TypeError(`Assignment to constant variable at ${ filename }:${ line }:${ column }`);
}
_compile.call(
module,
content.replace(matchConst, "$1let $2"), // replace const with let, while maintaining the column width
filename
);
};
restoreExtensions();
originalExtensions.js(module, filename);
}
function coffeeExtension(module, filename) {
if (!coffee) {
throw new Error("Cannot rewire module written in CoffeeScript: Please install 'coffeescript' package first.");
}
var content = stripBOM(fs.readFileSync(filename, "utf8"));
restoreExtensions();
content = coffee.compile(content, {
filename: filename,
bare: true
});
module._compile(content, filename);
}
/**
* @see https://github.com/joyent/node/blob/master/lib/module.js
*/
function stripBOM(content) {
// Remove byte order marker. This catches EF BB BF (the UTF-8 BOM)
// because the buffer-to-string conversion in `fs.readFileSync()`
// translates it to FEFF, the UTF-16 BOM.
if (content.charCodeAt(0) === 0xFEFF) {
content = content.slice(1);
}
return content;
}
try {
coffee = require("coffeescript");
} catch (err) {
try {
// Trying to load deprecated package
coffee = require("coffee-script");
} catch (err) {
// We are not able to provide CoffeeScript support, but that's ok as long as the user doesn't want it.
}
}
exports.load = load;
exports.inject = inject;
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