喔哦,Prepack 碉堡了!

2017-05-04

原文:https://medium.com/@dtinth/wow-prepack-is-awesome-b3d802590c42

刚刚试了一下几个小时前Facebook开源的项目Prepack.

这是我滴测试代码:

1
console.log(require('util').inspect({ hello: 'world!' }))

webpack 编译后:

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/* 0 */
/***/ (function(module, exports, __webpack_require__) {

/* WEBPACK VAR INJECTION */(function(global, process) {// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

var formatRegExp = /%[sdj%]/g;
exports.format = function(f) {
if (!isString(f)) {
var objects = [];
for (var i = 0; i < arguments.length; i++) {
objects.push(inspect(arguments[i]));
}
return objects.join(' ');
}

var i = 1;
var args = arguments;
var len = args.length;
var str = String(f).replace(formatRegExp, function(x) {
if (x === '%%') return '%';
if (i >= len) return x;
switch (x) {
case '%s': return String(args[i++]);
case '%d': return Number(args[i++]);
case '%j':
try {
return JSON.stringify(args[i++]);
} catch (_) {
return '[Circular]';
}
default:
return x;
}
});
for (var x = args[i]; i < len; x = args[++i]) {
if (isNull(x) || !isObject(x)) {
str += ' ' + x;
} else {
str += ' ' + inspect(x);
}
}
return str;
};


// Mark that a method should not be used.
// Returns a modified function which warns once by default.
// If --no-deprecation is set, then it is a no-op.
exports.deprecate = function(fn, msg) {
// Allow for deprecating things in the process of starting up.
if (isUndefined(global.process)) {
return function() {
return exports.deprecate(fn, msg).apply(this, arguments);
};
}

if (process.noDeprecation === true) {
return fn;
}

var warned = false;
function deprecated() {
if (!warned) {
if (process.throwDeprecation) {
throw new Error(msg);
} else if (process.traceDeprecation) {
console.trace(msg);
} else {
console.error(msg);
}
warned = true;
}
return fn.apply(this, arguments);
}

return deprecated;
};


var debugs = {};
var debugEnviron;
exports.debuglog = function(set) {
if (isUndefined(debugEnviron))
debugEnviron = process.env.NODE_DEBUG || '';
set = set.toUpperCase();
if (!debugs[set]) {
if (new RegExp('\\b' + set + '\\b', 'i').test(debugEnviron)) {
var pid = process.pid;
debugs[set] = function() {
var msg = exports.format.apply(exports, arguments);
console.error('%s %d: %s', set, pid, msg);
};
} else {
debugs[set] = function() {};
}
}
return debugs[set];
};


/**
* Echos the value of a value. Trys to print the value out
* in the best way possible given the different types.
*
* @param {Object} obj The object to print out.
* @param {Object} opts Optional options object that alters the output.
*/

/* legacy: obj, showHidden, depth, colors*/
function inspect(obj, opts) {
// default options
var ctx = {
seen: [],
stylize: stylizeNoColor
};
// legacy...
if (arguments.length >= 3) ctx.depth = arguments[2];
if (arguments.length >= 4) ctx.colors = arguments[3];
if (isBoolean(opts)) {
// legacy...
ctx.showHidden = opts;
} else if (opts) {
// got an "options" object
exports._extend(ctx, opts);
}
// set default options
if (isUndefined(ctx.showHidden)) ctx.showHidden = false;
if (isUndefined(ctx.depth)) ctx.depth = 2;
if (isUndefined(ctx.colors)) ctx.colors = false;
if (isUndefined(ctx.customInspect)) ctx.customInspect = true;
if (ctx.colors) ctx.stylize = stylizeWithColor;
return formatValue(ctx, obj, ctx.depth);
}
exports.inspect = inspect;


// http://en.wikipedia.org/wiki/ANSI_escape_code#graphics
inspect.colors = {
'bold' : [1, 22],
'italic' : [3, 23],
'underline' : [4, 24],
'inverse' : [7, 27],
'white' : [37, 39],
'grey' : [90, 39],
'black' : [30, 39],
'blue' : [34, 39],
'cyan' : [36, 39],
'green' : [32, 39],
'magenta' : [35, 39],
'red' : [31, 39],
'yellow' : [33, 39]
};

// Don't use 'blue' not visible on cmd.exe
inspect.styles = {
'special': 'cyan',
'number': 'yellow',
'boolean': 'yellow',
'undefined': 'grey',
'null': 'bold',
'string': 'green',
'date': 'magenta',
// "name": intentionally not styling
'regexp': 'red'
};


function stylizeWithColor(str, styleType) {
var style = inspect.styles[styleType];

if (style) {
return '\u001b[' + inspect.colors[style][0] + 'm' + str +
'\u001b[' + inspect.colors[style][1] + 'm';
} else {
return str;
}
}


function stylizeNoColor(str, styleType) {
return str;
}


function arrayToHash(array) {
var hash = {};

array.forEach(function(val, idx) {
hash[val] = true;
});

return hash;
}


function formatValue(ctx, value, recurseTimes) {
// Provide a hook for user-specified inspect functions.
// Check that value is an object with an inspect function on it
if (ctx.customInspect &&
value &&
isFunction(value.inspect) &&
// Filter out the util module, it's inspect function is special
value.inspect !== exports.inspect &&
// Also filter out any prototype objects using the circular check.
!(value.constructor && value.constructor.prototype === value)) {
var ret = value.inspect(recurseTimes, ctx);
if (!isString(ret)) {
ret = formatValue(ctx, ret, recurseTimes);
}
return ret;
}

// Primitive types cannot have properties
var primitive = formatPrimitive(ctx, value);
if (primitive) {
return primitive;
}

// Look up the keys of the object.
var keys = Object.keys(value);
var visibleKeys = arrayToHash(keys);

if (ctx.showHidden) {
keys = Object.getOwnPropertyNames(value);
}

// IE doesn't make error fields non-enumerable
// http://msdn.microsoft.com/en-us/library/ie/dww52sbt(v=vs.94).aspx
if (isError(value)
&& (keys.indexOf('message') >= 0 || keys.indexOf('description') >= 0)) {
return formatError(value);
}

// Some type of object without properties can be shortcutted.
if (keys.length === 0) {
if (isFunction(value)) {
var name = value.name ? ': ' + value.name : '';
return ctx.stylize('[Function' + name + ']', 'special');
}
if (isRegExp(value)) {
return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
}
if (isDate(value)) {
return ctx.stylize(Date.prototype.toString.call(value), 'date');
}
if (isError(value)) {
return formatError(value);
}
}

var base = '', array = false, braces = ['{', '}'];

// Make Array say that they are Array
if (isArray(value)) {
array = true;
braces = ['[', ']'];
}

// Make functions say that they are functions
if (isFunction(value)) {
var n = value.name ? ': ' + value.name : '';
base = ' [Function' + n + ']';
}

// Make RegExps say that they are RegExps
if (isRegExp(value)) {
base = ' ' + RegExp.prototype.toString.call(value);
}

// Make dates with properties first say the date
if (isDate(value)) {
base = ' ' + Date.prototype.toUTCString.call(value);
}

// Make error with message first say the error
if (isError(value)) {
base = ' ' + formatError(value);
}

if (keys.length === 0 && (!array || value.length == 0)) {
return braces[0] + base + braces[1];
}

if (recurseTimes < 0) {
if (isRegExp(value)) {
return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
} else {
return ctx.stylize('[Object]', 'special');
}
}

ctx.seen.push(value);

var output;
if (array) {
output = formatArray(ctx, value, recurseTimes, visibleKeys, keys);
} else {
output = keys.map(function(key) {
return formatProperty(ctx, value, recurseTimes, visibleKeys, key, array);
});
}

ctx.seen.pop();

return reduceToSingleString(output, base, braces);
}


function formatPrimitive(ctx, value) {
if (isUndefined(value))
return ctx.stylize('undefined', 'undefined');
if (isString(value)) {
var simple = '\'' + JSON.stringify(value).replace(/^"|"$/g, '')
.replace(/'/g, "\\'")
.replace(/\\"/g, '"') + '\'';
return ctx.stylize(simple, 'string');
}
if (isNumber(value))
return ctx.stylize('' + value, 'number');
if (isBoolean(value))
return ctx.stylize('' + value, 'boolean');
// For some reason typeof null is "object", so special case here.
if (isNull(value))
return ctx.stylize('null', 'null');
}


function formatError(value) {
return '[' + Error.prototype.toString.call(value) + ']';
}


function formatArray(ctx, value, recurseTimes, visibleKeys, keys) {
var output = [];
for (var i = 0, l = value.length; i < l; ++i) {
if (hasOwnProperty(value, String(i))) {
output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
String(i), true));
} else {
output.push('');
}
}
keys.forEach(function(key) {
if (!key.match(/^\d+$/)) {
output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
key, true));
}
});
return output;
}


function formatProperty(ctx, value, recurseTimes, visibleKeys, key, array) {
var name, str, desc;
desc = Object.getOwnPropertyDescriptor(value, key) || { value: value[key] };
if (desc.get) {
if (desc.set) {
str = ctx.stylize('[Getter/Setter]', 'special');
} else {
str = ctx.stylize('[Getter]', 'special');
}
} else {
if (desc.set) {
str = ctx.stylize('[Setter]', 'special');
}
}
if (!hasOwnProperty(visibleKeys, key)) {
name = '[' + key + ']';
}
if (!str) {
if (ctx.seen.indexOf(desc.value) < 0) {
if (isNull(recurseTimes)) {
str = formatValue(ctx, desc.value, null);
} else {
str = formatValue(ctx, desc.value, recurseTimes - 1);
}
if (str.indexOf('\n') > -1) {
if (array) {
str = str.split('\n').map(function(line) {
return ' ' + line;
}).join('\n').substr(2);
} else {
str = '\n' + str.split('\n').map(function(line) {
return ' ' + line;
}).join('\n');
}
}
} else {
str = ctx.stylize('[Circular]', 'special');
}
}
if (isUndefined(name)) {
if (array && key.match(/^\d+$/)) {
return str;
}
name = JSON.stringify('' + key);
if (name.match(/^"([a-zA-Z_][a-zA-Z_0-9]*)"$/)) {
name = name.substr(1, name.length - 2);
name = ctx.stylize(name, 'name');
} else {
name = name.replace(/'/g, "\\'")
.replace(/\\"/g, '"')
.replace(/(^"|"$)/g, "'");
name = ctx.stylize(name, 'string');
}
}

return name + ': ' + str;
}


function reduceToSingleString(output, base, braces) {
var numLinesEst = 0;
var length = output.reduce(function(prev, cur) {
numLinesEst++;
if (cur.indexOf('\n') >= 0) numLinesEst++;
return prev + cur.replace(/\u001b\[\d\d?m/g, '').length + 1;
}, 0);

if (length > 60) {
return braces[0] +
(base === '' ? '' : base + '\n ') +
' ' +
output.join(',\n ') +
' ' +
braces[1];
}

return braces[0] + base + ' ' + output.join(', ') + ' ' + braces[1];
}


// NOTE: These type checking functions intentionally don't use `instanceof`
// because it is fragile and can be easily faked with `Object.create()`.
function isArray(ar) {
return Array.isArray(ar);
}
exports.isArray = isArray;

function isBoolean(arg) {
return typeof arg === 'boolean';
}
exports.isBoolean = isBoolean;

function isNull(arg) {
return arg === null;
}
exports.isNull = isNull;

function isNullOrUndefined(arg) {
return arg == null;
}
exports.isNullOrUndefined = isNullOrUndefined;

function isNumber(arg) {
return typeof arg === 'number';
}
exports.isNumber = isNumber;

function isString(arg) {
return typeof arg === 'string';
}
exports.isString = isString;

function isSymbol(arg) {
return typeof arg === 'symbol';
}
exports.isSymbol = isSymbol;

function isUndefined(arg) {
return arg === void 0;
}
exports.isUndefined = isUndefined;

function isRegExp(re) {
return isObject(re) && objectToString(re) === '[object RegExp]';
}
exports.isRegExp = isRegExp;

function isObject(arg) {
return typeof arg === 'object' && arg !== null;
}
exports.isObject = isObject;

function isDate(d) {
return isObject(d) && objectToString(d) === '[object Date]';
}
exports.isDate = isDate;

function isError(e) {
return isObject(e) &&
(objectToString(e) === '[object Error]' || e instanceof Error);
}
exports.isError = isError;

function isFunction(arg) {
return typeof arg === 'function';
}
exports.isFunction = isFunction;

function isPrimitive(arg) {
return arg === null ||
typeof arg === 'boolean' ||
typeof arg === 'number' ||
typeof arg === 'string' ||
typeof arg === 'symbol' || // ES6 symbol
typeof arg === 'undefined';
}
exports.isPrimitive = isPrimitive;

exports.isBuffer = __webpack_require__(3);

function objectToString(o) {
return Object.prototype.toString.call(o);
}


function pad(n) {
return n < 10 ? '0' + n.toString(10) : n.toString(10);
}


var months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep',
'Oct', 'Nov', 'Dec'];

// 26 Feb 16:19:34
function timestamp() {
var d = new Date();
var time = [pad(d.getHours()),
pad(d.getMinutes()),
pad(d.getSeconds())].join(':');
return [d.getDate(), months[d.getMonth()], time].join(' ');
}


// log is just a thin wrapper to console.log that prepends a timestamp
exports.log = function() {
console.log('%s - %s', timestamp(), exports.format.apply(exports, arguments));
};


/**
* Inherit the prototype methods from one constructor into another.
*
* The Function.prototype.inherits from lang.js rewritten as a standalone
* function (not on Function.prototype). NOTE: If this file is to be loaded
* during bootstrapping this function needs to be rewritten using some native
* functions as prototype setup using normal JavaScript does not work as
* expected during bootstrapping (see mirror.js in r114903).
*
* @param {function} ctor Constructor function which needs to inherit the
* prototype.
* @param {function} superCtor Constructor function to inherit prototype from.
*/

exports.inherits = __webpack_require__(2);

exports._extend = function(origin, add) {
// Don't do anything if add isn't an object
if (!add || !isObject(add)) return origin;

var keys = Object.keys(add);
var i = keys.length;
while (i--) {
origin[keys[i]] = add[keys[i]];
}
return origin;
};

function hasOwnProperty(obj, prop) {
return Object.prototype.hasOwnProperty.call(obj, prop);
}

/* WEBPACK VAR INJECTION */}.call(exports, __webpack_require__(4), __webpack_require__(1)))

/***/ }),
/* 1 */
/***/ (function(module, exports) {

// shim for using process in browser
var process = module.exports = {};

// cached from whatever global is present so that test runners that stub it
// don't break things. But we need to wrap it in a try catch in case it is
// wrapped in strict mode code which doesn't define any globals. It's inside a
// function because try/catches deoptimize in certain engines.

var cachedSetTimeout;
var cachedClearTimeout;

function defaultSetTimout() {
throw new Error('setTimeout has not been defined');
}
function defaultClearTimeout () {
throw new Error('clearTimeout has not been defined');
}
(function () {
try {
if (typeof setTimeout === 'function') {
cachedSetTimeout = setTimeout;
} else {
cachedSetTimeout = defaultSetTimout;
}
} catch (e) {
cachedSetTimeout = defaultSetTimout;
}
try {
if (typeof clearTimeout === 'function') {
cachedClearTimeout = clearTimeout;
} else {
cachedClearTimeout = defaultClearTimeout;
}
} catch (e) {
cachedClearTimeout = defaultClearTimeout;
}
} ())
function runTimeout(fun) {
if (cachedSetTimeout === setTimeout) {
//normal enviroments in sane situations
return setTimeout(fun, 0);
}
// if setTimeout wasn't available but was latter defined
if ((cachedSetTimeout === defaultSetTimout || !cachedSetTimeout) && setTimeout) {
cachedSetTimeout = setTimeout;
return setTimeout(fun, 0);
}
try {
// when when somebody has screwed with setTimeout but no I.E. maddness
return cachedSetTimeout(fun, 0);
} catch(e){
try {
// When we are in I.E. but the script has been evaled so I.E. doesn't trust the global object when called normally
return cachedSetTimeout.call(null, fun, 0);
} catch(e){
// same as above but when it's a version of I.E. that must have the global object for 'this', hopfully our context correct otherwise it will throw a global error
return cachedSetTimeout.call(this, fun, 0);
}
}


}
function runClearTimeout(marker) {
if (cachedClearTimeout === clearTimeout) {
//normal enviroments in sane situations
return clearTimeout(marker);
}
// if clearTimeout wasn't available but was latter defined
if ((cachedClearTimeout === defaultClearTimeout || !cachedClearTimeout) && clearTimeout) {
cachedClearTimeout = clearTimeout;
return clearTimeout(marker);
}
try {
// when when somebody has screwed with setTimeout but no I.E. maddness
return cachedClearTimeout(marker);
} catch (e){
try {
// When we are in I.E. but the script has been evaled so I.E. doesn't trust the global object when called normally
return cachedClearTimeout.call(null, marker);
} catch (e){
// same as above but when it's a version of I.E. that must have the global object for 'this', hopfully our context correct otherwise it will throw a global error.
// Some versions of I.E. have different rules for clearTimeout vs setTimeout
return cachedClearTimeout.call(this, marker);
}
}



}
var queue = [];
var draining = false;
var currentQueue;
var queueIndex = -1;

function cleanUpNextTick() {
if (!draining || !currentQueue) {
return;
}
draining = false;
if (currentQueue.length) {
queue = currentQueue.concat(queue);
} else {
queueIndex = -1;
}
if (queue.length) {
drainQueue();
}
}

function drainQueue() {
if (draining) {
return;
}
var timeout = runTimeout(cleanUpNextTick);
draining = true;

var len = queue.length;
while(len) {
currentQueue = queue;
queue = [];
while (++queueIndex < len) {
if (currentQueue) {
currentQueue[queueIndex].run();
}
}
queueIndex = -1;
len = queue.length;
}
currentQueue = null;
draining = false;
runClearTimeout(timeout);
}

process.nextTick = function (fun) {
var args = new Array(arguments.length - 1);
if (arguments.length > 1) {
for (var i = 1; i < arguments.length; i++) {
args[i - 1] = arguments[i];
}
}
queue.push(new Item(fun, args));
if (queue.length === 1 && !draining) {
runTimeout(drainQueue);
}
};

// v8 likes predictible objects
function Item(fun, array) {
this.fun = fun;
this.array = array;
}
Item.prototype.run = function () {
this.fun.apply(null, this.array);
};
process.title = 'browser';
process.browser = true;
process.env = {};
process.argv = [];
process.version = ''; // empty string to avoid regexp issues
process.versions = {};

function noop() {}

process.on = noop;
process.addListener = noop;
process.once = noop;
process.off = noop;
process.removeListener = noop;
process.removeAllListeners = noop;
process.emit = noop;
process.prependListener = noop;
process.prependOnceListener = noop;

process.listeners = function (name) { return [] }

process.binding = function (name) {
throw new Error('process.binding is not supported');
};

process.cwd = function () { return '/' };
process.chdir = function (dir) {
throw new Error('process.chdir is not supported');
};
process.umask = function() { return 0; };


/***/ }),
/* 2 */
/***/ (function(module, exports) {

if (typeof Object.create === 'function') {
// implementation from standard node.js 'util' module
module.exports = function inherits(ctor, superCtor) {
ctor.super_ = superCtor
ctor.prototype = Object.create(superCtor.prototype, {
constructor: {
value: ctor,
enumerable: false,
writable: true,
configurable: true
}
});
};
} else {
// old school shim for old browsers
module.exports = function inherits(ctor, superCtor) {
ctor.super_ = superCtor
var TempCtor = function () {}
TempCtor.prototype = superCtor.prototype
ctor.prototype = new TempCtor()
ctor.prototype.constructor = ctor
}
}


/***/ }),
/* 3 */
/***/ (function(module, exports) {

module.exports = function isBuffer(arg) {
return arg && typeof arg === 'object'
&& typeof arg.copy === 'function'
&& typeof arg.fill === 'function'
&& typeof arg.readUInt8 === 'function';
}

/***/ }),
/* 4 */
/***/ (function(module, exports) {

var g;

// This works in non-strict mode
g = (function() {
return this;
})();

try {
// This works if eval is allowed (see CSP)
g = g || Function("return this")() || (1,eval)("this");
} catch(e) {
// This works if the window reference is available
if(typeof window === "object")
g = window;
}

// g can still be undefined, but nothing to do about it...
// We return undefined, instead of nothing here, so it's
// easier to handle this case. if(!global) { ...}

module.exports = g;


/***/ }),
/* 5 */
/***/ (function(module, exports, __webpack_require__) {


console.log(__webpack_require__(0).inspect({ hello: 'world!' }))


/***/ })
/******/ ]);

把这900多行的代码放到prepack之后, 结果是!!!:

1
console.log("{ hello: 'world!' }");

碉!堡!了!有木有。。。

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