node/lib/console.js

102 строки
2.6 KiB
JavaScript

'use strict';
const util = require('util');
function Console(stdout, stderr) {
if (!(this instanceof Console)) {
return new Console(stdout, stderr);
}
if (!stdout || typeof stdout.write !== 'function') {
throw new TypeError('Console expects a writable stream instance');
}
if (!stderr) {
stderr = stdout;
} else if (typeof stderr.write !== 'function') {
throw new TypeError('Console expects writable stream instances');
}
var prop = {
writable: true,
enumerable: false,
configurable: true
};
prop.value = stdout;
Object.defineProperty(this, '_stdout', prop);
prop.value = stderr;
Object.defineProperty(this, '_stderr', prop);
prop.value = new Map();
Object.defineProperty(this, '_times', prop);
// bind the prototype functions to this Console instance
var keys = Object.keys(Console.prototype);
for (var v = 0; v < keys.length; v++) {
var k = keys[v];
this[k] = this[k].bind(this);
}
}
// As of v8 5.0.71.32, the combination of rest param, template string
// and .apply(null, args) benchmarks consistently faster than using
// the spread operator when calling util.format.
Console.prototype.log = function(...args) {
this._stdout.write(`${util.format.apply(null, args)}\n`);
};
Console.prototype.info = Console.prototype.log;
Console.prototype.warn = function(...args) {
this._stderr.write(`${util.format.apply(null, args)}\n`);
};
Console.prototype.error = Console.prototype.warn;
Console.prototype.dir = function(object, options) {
options = Object.assign({customInspect: false}, options);
this._stdout.write(`${util.inspect(object, options)}\n`);
};
Console.prototype.time = function(label) {
this._times.set(label, process.hrtime());
};
Console.prototype.timeEnd = function(label) {
const time = this._times.get(label);
if (!time) {
process.emitWarning(`No such label '${label}' for console.timeEnd()`);
return;
}
const duration = process.hrtime(time);
const ms = duration[0] * 1000 + duration[1] / 1e6;
this.log('%s: %sms', label, ms.toFixed(3));
this._times.delete(label);
};
Console.prototype.trace = function trace(...args) {
// TODO probably can to do this better with V8's debug object once that is
// exposed.
var err = new Error();
err.name = 'Trace';
err.message = util.format.apply(null, args);
Error.captureStackTrace(err, trace);
this.error(err.stack);
};
Console.prototype.assert = function(expression, ...args) {
if (!expression) {
require('assert').ok(false, util.format.apply(null, args));
}
};
module.exports = new Console(process.stdout, process.stderr);
module.exports.Console = Console;