如果我将文件的内容作为内存中的字符串，而不将其写入磁盘，我将如何要求（）文件？这是一个例子：
// Load the file as a string
var strFileContents = fs.readFileSync( "./myUnalteredModule.js", 'utf8' );
// Do some stuff to the files contents
strFileContents[532] = '6';
// Load it as a node module (how would I do this?)
var loadedModule = require( doMagic(strFileContents) );
function requireFromString(src, filename) {
var Module = module.constructor;
var m = new Module();
m._compile(src, filename);
return m.exports;
}
console.log(requireFromString('module.exports = { test: 1}'));
查看module.js中的_compile，_extensions和_load
安德烈已经回答了这个问题，但是我遇到了一个我必须解决的缺点，这可能是其他人感兴趣的。
我希望记忆字符串中的模块能够通过require加载其他模块，但模块路径被上述解决方案破坏了（例如没有找到针）。我试图找到一个优雅的解决方案来维护路径，通过使用一些现有的功能，但我最终与路径硬连线：
function requireFromString(src, filename) {
var m = new module.constructor();
m.paths = module.paths;
m._compile(src, filename);
return m.exports;
}
var codeString = 'var needle = require(\'needle\');\n'
+ '[...]\n'
+ 'exports.myFunc = myFunc;';
var virtMod = requireFromString(codeString);
console.log('Available public functions: '+Object.keys(virtMod));
之后，我能够从stringified模块加载所有现有模块。任何评论或更好的解决方案高度赞赏
require-from-string package完成了这项工作。
用法：
var requireFromString = require('require-from-string');
requireFromString('module.exports = 1');
//=> 1
基于Andrey Sidorov和Dominic的解决方案，我对无法使用字符串模块的事实感到很难过，因此我建议使用此版本*。
码：
void function() {
'use strict';
const EXTENSIONS = ['.js', '.json', '.node'];
var Module,
path,
cache,
resolveFilename,
demethodize,
hasOwnProperty,
dirname,
parse,
resolve,
stringify,
virtual;
Module = require('module');
path = require('path');
cache = Module._cache;
resolveFilename = Module._resolveFilename;
dirname = path.dirname;
parse = path.parse;
resolve = path.resolve;
demethodize = Function.bind.bind(Function.call);
hasOwnProperty = demethodize(Object.prototype.hasOwnProperty);
Module._resolveFilename = function(request, parent) {
var filename;
// Pre-resolution
filename = resolve(parse(parent.filename).dir, request);
// Adding extension, if needed
if (EXTENSIONS.indexOf(parse(filename).ext) === -1) {
filename += '.js';
}
// If the module exists or is virtual, return the filename
if (virtual || hasOwnProperty(cache, filename)) {
return filename;
}
// Preserving the native behavior
return resolveFilename.apply(Module, arguments);
};
Module._register = function(request, parent, src) {
var filename,
module;
// Enabling virtual resolution
virtual = true;
filename = Module._resolveFilename(request, parent);
// Disabling virtual resolution
virtual = false;
// Conflicts management
if (hasOwnProperty(cache, filename)) {
error = new Error('Existing module "' + request + '"');
error.code = 'MODULE_EXISTS';
throw error;
}
// Module loading
cache[filename] = module = new Module(filename, parent);
module.filename = filename;
module.paths = Module._nodeModulePaths(dirname(filename));
module._compile(stringify(src), filename);
module.loaded = true;
return module;
};
stringify = function(src) {
// If src is a function, turning to IIFE src
return typeof src === 'function'
? 'void ' + src.toString() + '();'
: src;
};
}();
void function() {
var Module,
parentModule,
child;
Module = require('module');
// Creating a parent module from string
parentModule = Module._register('parent', process.mainModule, `
module.exports = {
name: module.filename,
getChild: function() {
return require('child');
}
};
`);
// Creating a child module from function
Module._register('child', parentModule, function() {
module.exports = {
name: module.filename,
getParent: function() {
return module.parent.exports;
}
};
});
child = require('child');
console.log(child === child.getParent().getChild());
}();
用法：
void function() {
var Module,
parentModule,
child;
Module = require('module');
// Creating a parent module from string
parentModule = Module._register('parent', process.mainModule, `
module.exports = {
name: module.filename,
getChild: function() {
return require('child');
}
};
`);
// Creating a child module from function
Module._register('child', parentModule, function() {
module.exports = {
name: module.filename,
getParent: function() {
return module.parent.exports;
}
};
});
child = require('child');
console.log(child === child.getParent().getChild());
}();
*如您所见，它包含一个函数格式化程序，它提供了一种从函数创建一些模块的方法。
在分析了pirates和require-from-string等解决方案的源代码之后，我得出的结论是，在支持方面，对fs和Module方法的简单模拟不会更糟。在功能方面它会更好，因为它支持@babel/register，pirates和其他模块来改变模块加载过程。
你可以尝试这个npm模块require-from-memory
import fs from 'fs'
import BuiltinModule from 'module'
const Module = module.constructor.length > 1 ? module.constructor : BuiltinModule
function requireFromString(code, filename) {
if (!filename) {
filename = ''
}
if (typeof filename !== 'string') {
throw new Error(`filename must be a string: ${filename}`)
}
let buffer
function getBuffer() {
if (!buffer) {
buffer = Buffer.from(code, 'utf8')
}
return buffer
}
const now = new Date()
const nowMs = now.getTime()
const size = Buffer.byteLength(code, 'utf8')
const fileStat = {
size,
blksize : 4096,
blocks : Math.ceil(size / 4096),
atimeMs : nowMs,
mtimeMs : nowMs,
ctimeMs : nowMs,
birthtimeMs: nowMs,
atime : now,
mtime : now,
ctime : now,
birthtime : now
}
const resolveFilename = Module._resolveFilename
const readFileSync = fs.readFileSync
const statSync = fs.statSync
try {
Module._resolveFilename = () => {
Module._resolveFilename = resolveFilename
return filename
}
fs.readFileSync = (fname, options, ...other) => {
if (fname === filename) {
console.log(code)
return typeof options === 'string'
? code
: getBuffer()
}
console.log(code)
return readFileSync.apply(fs, [fname, options, ...other])
}
fs.statSync = (fname, ...other) => {
if (fname === filename) {
return fileStat
}
return statSync.apply(fs, [fname, ...other])
}
return require(filename)
} finally {
Module._resolveFilename = resolveFilename
fs.readFileSync = readFileSync
fs.statSync = statSync
}
}
我认为更好的方法是获得一个你可以在之后设置的参数......
比如文件里面：myUnalteredModule.js
exports.setChanges = function( args )...
然后你可以这样做：
var loadedModule = require( 'myUnalteredModule' );
loadedModule