'use strict'; require('../common'); const assert = require('assert'); const util = require('util'); const symbol = Symbol('foo'); assert.equal(util.format(), ''); assert.equal(util.format(''), ''); assert.equal(util.format([]), '[]'); assert.equal(util.format({}), '{}'); assert.equal(util.format(null), 'null'); assert.equal(util.format(true), 'true'); assert.equal(util.format(false), 'false'); assert.equal(util.format('test'), 'test'); // CHECKME this is for console.log() compatibility - but is it *right*? assert.equal(util.format('foo', 'bar', 'baz'), 'foo bar baz'); // ES6 Symbol handling assert.equal(util.format(symbol), 'Symbol(foo)'); assert.equal(util.format('foo', symbol), 'foo Symbol(foo)'); assert.equal(util.format('%s', symbol), 'Symbol(foo)'); assert.equal(util.format('%j', symbol), 'undefined'); assert.throws(function() { util.format('%d', symbol); }, TypeError); assert.equal(util.format('%d', 42.0), '42'); assert.equal(util.format('%d', 42), '42'); assert.equal(util.format('%s', 42), '42'); assert.equal(util.format('%j', 42), '42'); assert.equal(util.format('%d', '42.0'), '42'); assert.equal(util.format('%d', '42'), '42'); assert.equal(util.format('%s', '42'), '42'); assert.equal(util.format('%j', '42'), '"42"'); assert.equal(util.format('%%s%s', 'foo'), '%sfoo'); assert.equal(util.format('%s'), '%s'); assert.equal(util.format('%s', undefined), 'undefined'); assert.equal(util.format('%s', 'foo'), 'foo'); assert.equal(util.format('%s:%s'), '%s:%s'); assert.equal(util.format('%s:%s', undefined), 'undefined:%s'); assert.equal(util.format('%s:%s', 'foo'), 'foo:%s'); assert.equal(util.format('%s:%s', 'foo', 'bar'), 'foo:bar'); assert.equal(util.format('%s:%s', 'foo', 'bar', 'baz'), 'foo:bar baz'); assert.equal(util.format('%%%s%%', 'hi'), '%hi%'); assert.equal(util.format('%%%s%%%%', 'hi'), '%hi%%'); (function() { var o = {}; o.o = o; assert.equal(util.format('%j', o), '[Circular]'); })(); // Errors const err = new Error('foo'); assert.equal(util.format(err), err.stack); function CustomError(msg) { Error.call(this); Object.defineProperty(this, 'message', { value: msg, enumerable: false }); Object.defineProperty(this, 'name', { value: 'CustomError', enumerable: false }); Error.captureStackTrace(this, CustomError); } util.inherits(CustomError, Error); const customError = new CustomError('bar'); assert.equal(util.format(customError), customError.stack); // Doesn't capture stack trace function BadCustomError(msg) { Error.call(this); Object.defineProperty(this, 'message', { value: msg, enumerable: false }); Object.defineProperty(this, 'name', { value: 'BadCustomError', enumerable: false }); } util.inherits(BadCustomError, Error); assert.equal(util.format(new BadCustomError('foo')), '[BadCustomError: foo]');