buster-format

Version:

0.4.0 (2011-08-10)

Module:

var format = require("buster-format");

In browsers:

var format = buster.format;

Utility functions with helpers for pretty formatting of arbitrary JavaScript values. Currently only supports ascii formatting, suitable for command-line utilities. Like JSON.stringify, it formats objects recursively, but unlike JSON.stringify, it can handle regular expressions, functions and more.

Methods

format.ascii(object)

format.ascii() can take any JavaScript object, including DOM elements, and format it nicely as plain text. It uses the helper functions described below to format different types of objects.

Simple object

var format = require("buster-format");

var object = {
    name: "Christian"
};

console.log(format.ascii(object));

// Outputs:
// { name: "Christian" }

Complex object

var format = require("buster-format");

var developer = {
    name: "Christian",
    interests: ["Programming", "Guitar", "TV"],

    location: {
        language: "Norway",
        city: "Oslo",

        getLatLon: function getLatLon(callback) {
            // ...
        },

        distanceTo: function distanceTo(location) {
        }
    },

    speak: function () {
        return "Oh hi!";
    }
};

console.log(format.ascii(developer));

// Outputs:
// {
//   interests: ["Programming", "Guitar", "TV"],
//   location: {
//     city: "Oslo",
//     distanceTo: function distanceTo() {},
//     getLatLon: function getLatLon() {},
//     language: "Norway"
//   },
//   name: "Christian",
//   speak: function () {}
// }

Custom constructor

If the object to format is not a generic Object object, buster-format displays the type of object (i.e. name of constructor). Set the format.excludeConstructors property to control what constructors to include in formatted output.

var format = require("buster-format");

function Person(name) {
    this.name = name;
}

var dude = new Person("Dude");
console.log(format.ascii(dude));

// Outputs:
// [Person] { name: "Dude" }

DOM elements

DOM elements are formatted as abbreviated HTML source. 20 characters of innerHTML is included, and if the content is longer, it is truncated with "[...]". Future editions will add the possibility to format nested markup structures.

var p = document.createElement("p");
p.id = "sample";
p.className = "notice";
p.setAttribute("data-custom", "42");
p.innerHTML = "Hey there, here's some text for ya there buddy";

console.log(buster.format.ascii(p));

// Outputs
// <p id="sample" class="notice" data-custom="42">Hey there, here's so[...]</p>

format.ascii.functionName(func)

Guesses a function’s name. If the function defines the displayName property (used by some debugging tools) it is preferred. If it is not found, the name property is tried. If no name can be found this way, an attempt is made to find the function name by looking at the function’s toString() representation.

format.ascii.func(func)

Formats a function like "function [name]() {}". The name is retrieved from format.ascii.functionName().

format.ascii.array(array)

Formats an array as "[item1, item2, item3]" where each item is formatted with format.ascii(). Circular references are represented in the resulting string as "[Circular]".

format.ascii.object(object)

Formats all properties of the object with format.ascii(). If the object can be fully represented in 80 characters, it’s formatted in one line. Otherwise, it’s nicely indented over as many lines as necessary. Circular references are represented by "[Circular]".

Objects created with custom constructors will be formatted as "[ConstructorName] { ... }". Set the format.excludeConstructors property to control what constructors are included in the output like this.

format.ascii.element(element)

Formats a DOM element as HTML source. The tag name is represented in lower-case and all attributes and their values are included. The element’s content is included, up to 20 characters. If the length exceeds 20 characters, it’s truncated with a "[...]".

format.ascii.constructorName(object)

Attempts to guess the name of the constructor that created the object. It does so by getting the name of object.constructor using format.ascii.functionName(). If a name is found, format.excludeConstructors is consulted. If the constructor name matches any of these elements, an empty string is returned, otherwise the name is returned.

Properties

format.quoteStrings

Default: true

Whether or not to quote simple strings. When set to false, simple strings are not quoted. Strings in arrays and objects will still be quoted, but ascii("Some string") will not gain additional quotes.

format.excludeConstructors

Default: ["Object", /^.$/]

An array of strings and/or regular expressions naming constructors that should be stripped from the formatted output. The default value skips objects created by Object and constructors that have one character names (which are typically used in Object.create shims).

While you can set this property directly on format.ascii, it is recommended to create an instance of format.ascii and override the property on that object.

Strings represent constructor names that should not be represented in the formatted output. Regular expressions are tested against constructor names when formatting. If the expression is a match, the constructor name is not included in the formatted output.

function Person(name) {
    this.name = name;
}

var person = new Person("Chris");

console.log(buster.format.ascii(person));

// Outputs
// [Person] { name: "Chris" }

var formatter = Object.create(buster.format);
formatter.excludeConstructors = ["Object", /^.$/, "Person"];
console.log(formatter.ascii(person));

// Outputs
// { name: "Chris" }

// Global overwrite, generally not recommended
buster.format.excludeConstructors = ["Object", /^.$/, "Person"];
console.log(buster.format.ascii(person));

// Outputs
// { name: "Chris" }