index.js

#!/usr/bin/env node
'use strict';

var path = require('path');
var mdeps = require('module-deps');
var concat = require('concat-stream');
var esprima = require('esprima');
var estraverse = require('estraverse');
var estemplate = require('estemplate');
var escodegen = require('escodegen');
var xtend = require('xtend');

var dynamicRequires;

// core modules for node.js v0.12.7
// https://github.com/nodejs/node/blob/db1087c9757c31a82c50a1eba368d8cba95b57d0/lib/internal/module.js
var builtins = ['assert', 'buffer', 'child_process', 'cluster',
	'crypto', 'dgram', 'dns', 'domain', 'events', 'fs', 'http', 'https', 'net',
	'os', 'path', 'punycode', 'querystring', 'readline', 'repl', 'stream',
	'string_decoder', 'tls', 'tty', 'url', 'util', 'v8', 'vm', 'zlib'];

function initMap(moduleDeps) {
	var modIDtoName = Object.create(null);
	moduleDeps.forEach(function (dep) {
		var name;
		var ext = path.extname(dep.id);
		if (ext === '.js') {
			name = path.basename(dep.id, '.js').replace(/-/g, '_');
			name = '_mod_' + name;
		}
		else if (ext === '.json') {
			name = path.basename(dep.id, '.json').replace(/-/g, '_');
			name = '_mod_' + name;
		}
		else {
			throw ext + ' filename extension not supported';
		}
		var next = -1;
		var re = new RegExp(name + '(\\d*)$');
		for (var id in modIDtoName) {
			var result = re.exec(modIDtoName[id]);
			if (result) {
				if (result[1] === '') {
					next = 0;
					continue;
				}
				var count = parseInt(result[1], 10);
				if (next <= count) next = count + 1;
			}
		}
		if (next >= 0) name = name + next;
		modIDtoName[dep.id] = name;
	});
	return modIDtoName;
}

function wrapModule(module, modIDtoName) {
	var modAST = esprima.parse(module.source, { loc: true });
	// wrap the module code in a function declaration, set the exports alias (node.js) and return exported API
	var ast = estemplate('function <%= modName %>(module) {var exports = module.exports; %= body %; return module.exports}', {
		modName: {type: 'Identifier', name: modIDtoName[module.id]},
		body: modAST.body
	});
	// replace the require calls in the module code by function calls
	estraverse.replace(ast, {
		enter: function (node) {
			if (node.type === 'CallExpression' && node.callee.name === 'require') {
				if (node.arguments[0].type !== 'Literal') {
					var start = node.loc.start, end = node.loc.end;
					console.log(module.id + ':' + start.line + ':' + start.column + ':' + end.line + ':' + end.column + ': dynamic require call');
					dynamicRequires = true;
					this.skip();
				}
				// get the module name in the string argument of the require call
				var reqModID = module.deps[node.arguments[0].value];
				// if required module is a node.js module, skip
				if (!reqModID) return this.skip();
				// and replace it by a function call
				var replaced;
				if (path.extname(reqModID) === '.json') {
					replaced = estemplate('<%= modName %>();', {
						modName: {type: 'Identifier', name: modIDtoName[reqModID]}
					});
				}
				else {
					replaced = estemplate('<%= modName %>({exports: {}});', {
						modName: {type: 'Identifier', name: modIDtoName[reqModID]}
					});
				}
				return replaced.body[0].expression;
			}
		}
	});
	// return the AST of the module function declaration
	return ast.body[0];
}

function wrapJSONModule(module, modIDtoName) {
	// a hack to parse json in esprima
	var expr = esprima.parse('(' + module.source + ');');
	var jsonAST = expr.body[0].expression;
	var ast = estemplate('function <%= modName %>() { return <%= object %>; }', {
		modName: {type: 'Identifier', name: modIDtoName[module.id]},
		object: jsonAST
	});
	return ast.body[0];
}

module.exports = Spack;

function Spack (file, opts) {
	if (!opts) opts = {};
	var mopts = xtend(opts);
	if (opts.node) {
		mopts.filter = function (id) {
			if (builtins.indexOf(id) < 0) return true;
			return false;
		};
	}
	var md = mdeps(opts);
	md.end(file);
	return new Promise (function (fulfill, reject) {
		md.pipe(concat(function (moduleDeps) {
			dynamicRequires = false;
			var entry;
			var program = { "type": "Program", "body": [], "sourceType": "script" };
			var modIDtoName = initMap(moduleDeps);
			moduleDeps.forEach(function (dep) {
				var ast;
				if (path.extname(dep.id) === '.json') {
					ast = wrapJSONModule(dep, modIDtoName);
				}
				else {
					ast = wrapModule(dep, modIDtoName);
				}
				if (dep.entry) {
					entry = dep.id;
				}
				program.body.push(ast);
			});
			var entryPoint = estemplate('<%= modName %>({exports: {}});', {
				modName: {type: 'Identifier', name: modIDtoName[entry]}
			});
			program.body.push(entryPoint.body[0]);
			if (dynamicRequires) {
				reject(new Error("Can't handle dynamic arguments to require calls. Consider refactoring the code."));
			} else {
				fulfill(escodegen.generate(program));
			}
		}));
	});
}