hoek

General purpose node utilities

Lead Maintainer: Nathan LaFreniere

Table of Contents

• Introduction
• Object
  • clone
  • cloneWithShallow
  • merge
  • applyToDefaults
  • applyToDefaultsWithShallow
  • deepEqual
  • unique
  • mapToObject
  • intersect
  • flatten
  • reach
  • transform
• Timer
• Bench
• Binary Encoding/Decoding
  • base64urlEncode
  • base64urlDecode
• Escaping Characters
  • escapeHtml
  • escapeHeaderAttribute
  • escapeRegex
• Errors
  • assert
  • abort
  • displayStack
  • callStack
• Function
  • nextTick
  • once
  • ignore
• Miscellaneous
  • uniqueFilename

Introduction

The Hoek general purpose node utilities library is used to aid in a variety of manners. It comes with useful methods for Arrays (clone, merge, applyToDefaults), Objects (removeKeys, copy), Asserting and more.

For example, to use Hoek to set configuration with default options:

var Hoek = require('hoek');

var default = {url : "www.github.com", port : "8000", debug : true};

var config = Hoek.applyToDefaults(default, {port : "3000", admin : true});

// In this case, config would be { url: 'www.github.com', port: '3000', debug: true, admin: true }

Under each of the sections (such as Array), there are subsections which correspond to Hoek methods. Each subsection will explain how to use the corresponding method. In each js excerpt below, the var Hoek = require('hoek'); is omitted for brevity.

Object

Hoek provides several helpful methods for objects and arrays.

clone(obj)

This method is used to clone an object or an array. A deep copy is made (duplicates everything, including values that are objects).

var nestedObj = {
        w: /^something$/ig,
        x: {
            a: [1, 2, 3],
            b: 123456,
            c: new Date()
        },
        y: 'y',
        z: new Date()
    };

var copy = Hoek.clone(nestedObj);

copy.x.b = 100;

console.log(copy.y);        // results in 'y'
console.log(nestedObj.x.b); // results in 123456
console.log(copy.x.b);      // results in 100

cloneWithShallow(obj, keys)

keys is an array of key names to shallow copy

This method is also used to clone an object or array, however any keys listed in the keys array are shallow copied while those not listed are deep copied.

var nestedObj = {
        w: /^something$/ig,
        x: {
            a: [1, 2, 3],
            b: 123456,
            c: new Date()
        },
        y: 'y',
        z: new Date()
    };

var copy = Hoek.cloneWithShallow(nestedObj, ['x']);

copy.x.b = 100;

console.log(copy.y);        // results in 'y'
console.log(nestedObj.x.b); // results in 100
console.log(copy.x.b);      // results in 100

merge(target, source, isNullOverride, isMergeArrays)

isNullOverride, isMergeArrays default to true

Merge all the properties of source into target, source wins in conflict, and by default null and undefined from source are applied. Merge is destructive where the target is modified. For non destructive merge, use applyToDefaults.

var target = {a: 1, b : 2};
var source = {a: 0, c: 5};
var source2 = {a: null, c: 5};

Hoek.merge(target, source);         // results in {a: 0, b: 2, c: 5}
Hoek.merge(target, source2);        // results in {a: null, b: 2, c: 5}
Hoek.merge(target, source2, false); // results in {a: 1, b: 2, c: 5}

var targetArray = [1, 2, 3];
var sourceArray = [4, 5];

Hoek.merge(targetArray, sourceArray);              // results in [1, 2, 3, 4, 5]
Hoek.merge(targetArray, sourceArray, true, false); // results in [4, 5]

applyToDefaults(defaults, options)

Apply options to a copy of the defaults

var defaults = { host: "localhost", port: 8000 };
var options = { port: 8080 };

var config = Hoek.applyToDefaults(defaults, options); // results in { host: "localhost", port: 8080 }

applyToDefaultsWithShallow(defaults, options, keys)

keys is an array of key names to shallow copy

Apply options to a copy of the defaults. Keys specified in the last parameter are shallow copied from options instead of merged.

var defaults = {
        server: {
            host: "localhost",
            port: 8000
        },
        name: 'example'
    };

var options = { server: { port: 8080 } };

var config = Hoek.applyToDefaults(defaults, options); // results in { server: { port: 8080 }, name: 'example' }

deepEqual(b, a)

Performs a deep comparison of the two values including support for circular dependencies, prototype, and properties.

Hoek.deepEqual({ a: [1, 2], b: 'string', c: { d: true } }, { a: [1, 2], b: 'string', c: { d: true } });

unique(array, key)

Remove duplicate items from Array

var array = [1, 2, 2, 3, 3, 4, 5, 6];

var newArray = Hoek.unique(array);    // results in [1,2,3,4,5,6]

array = [{id: 1}, {id: 1}, {id: 2}];

newArray = Hoek.unique(array, "id");  // results in [{id: 1}, {id: 2}]

mapToObject(array, key)

Convert an Array into an Object

var array = [1,2,3];
var newObject = Hoek.mapToObject(array);   // results in [{"1": true}, {"2": true}, {"3": true}]

array = [{id: 1}, {id: 2}];
newObject = Hoek.mapToObject(array, "id"); // results in [{"id": 1}, {"id": 2}]

intersect(array1, array2)

Find the common unique items in two arrays

var array1 = [1, 2, 3];
var array2 = [1, 4, 5];

var newArray = Hoek.intersect(array1, array2); // results in [1]

flatten(array, [target])

Flatten an array

var array = [1, [2, 3]];

var flattenedArray = Hoek.flatten(array); // results in [1, 2, 3]

array = [1, [2, 3]];
target = [4, [5]];

flattenedArray = Hoek.flatten(array, target); // results in [4, [5], 1, 2, 3]

reach(obj, chain, [options])

Converts an object key chain string to reference

• options - optional settings
  • separator - string to split chain path on, defaults to '.'
  • default - value to return if the path or value is not present, default is undefined
  • strict - if true, will throw an error on missing member, default is false
  • functions - if true allow traversing functions for properties. false will throw an error if a function is part of the chain.

var chain = 'a.b.c';
var obj = {a : {b : { c : 1}}};

Hoek.reach(obj, chain); // returns 1

transform(obj, transform, [options])

Transforms an existing object into a new one based on the supplied obj and transform map. options are the same as the reach options.

var source = {
    address: {
        one: '123 main street',
        two: 'PO Box 1234'
    },
    title: 'Warehouse',
    state: 'CA'
};

var result = Hoek.transform(source, {
    'person.address.lineOne': 'address.one',
    'person.address.lineTwo': 'address.two',
    'title': 'title',
    'person.address.region': 'state'
});
// Results in
// {
//     person: {
//         address: {
//             lineOne: '123 main street',
//             lineTwo: 'PO Box 1234',
//             region: 'CA'
//         }
//     },
//     title: 'Warehouse'
// }

Timer

A Timer object. Initializing a new timer object sets the ts to the number of milliseconds elapsed since 1 January 1970 00:00:00 UTC.

var timerObj = new Hoek.Timer();
console.log("Time is now: " + timerObj.ts);
console.log("Elapsed time from initialization: " + timerObj.elapsed() + 'milliseconds');

Bench

Same as Timer with the exception that ts stores the internal node clock which is not related to Date.now() and cannot be used to display human-readable timestamps. More accurate for benchmarking or internal timers.

Binary Encoding/Decoding

base64urlEncode(value)

Encodes value in Base64 or URL encoding

base64urlDecode(value)

Decodes data in Base64 or URL encoding.

Escaping Characters

Hoek provides convenient methods for escaping html characters. The escaped characters are as followed:

internals.htmlEscaped = {
    '&': '&',
    '<': '&lt;',
    '>': '&gt;',
    '"': '&quot;',
    "'": '&#x27;',
    '`': '&#x60;'
};

escapeHtml(string)

var string = '<html> hey </html>';
var escapedString = Hoek.escapeHtml(string); // returns &lt;html&gt; hey &lt;/html&gt;

escapeHeaderAttribute(attribute)

Escape attribute value for use in HTTP header

var a = Hoek.escapeHeaderAttribute('I said "go w\\o me"');  //returns I said \"go w\\o me\"

escapeRegex(string)

Escape string for Regex construction

var a = Hoek.escapeRegex('4^f$s.4*5+-_?%=#!:@|~\\/`"(>)[<]d{}s,');  // returns 4\^f\$s\.4\*5\+\-_\?%\=#\!\:@\|~\\\/`"\(>\)\[<\]d\{\}s\,

Errors

assert(message)

var a = 1, b =2;

Hoek.assert(a === b, 'a should equal b');  // ABORT: a should equal b

abort(message)

First checks if process.env.NODE_ENV === 'test', and if so, throws error message. Otherwise, displays most recent stack and then exits process.

displayStack(slice)

Displays the trace stack

var stack = Hoek.displayStack();
console.log(stack); // returns something like:

[ 'null (/Users/user/Desktop/hoek/test.js:4:18)',
  'Module._compile (module.js:449:26)',
  'Module._extensions..js (module.js:467:10)',
  'Module.load (module.js:356:32)',
  'Module._load (module.js:312:12)',
  'Module.runMain (module.js:492:10)',
  'startup.processNextTick.process._tickCallback (node.js:244:9)' ]

callStack(slice)

Returns a trace stack array.

var stack = Hoek.callStack();
console.log(stack);  // returns something like:

[ [ '/Users/user/Desktop/hoek/test.js', 4, 18, null, false ],
  [ 'module.js', 449, 26, 'Module._compile', false ],
  [ 'module.js', 467, 10, 'Module._extensions..js', false ],
  [ 'module.js', 356, 32, 'Module.load', false ],
  [ 'module.js', 312, 12, 'Module._load', false ],
  [ 'module.js', 492, 10, 'Module.runMain', false ],
  [ 'node.js',
    244,
    9,
    'startup.processNextTick.process._tickCallback',
    false ] ]

Function

nextTick(fn)

Returns a new function that wraps fn in process.nextTick.

var myFn = function () {
    console.log('Do this later');
};

var nextFn = Hoek.nextTick(myFn);

nextFn();
console.log('Do this first');

// Results in:
// 
// Do this first
// Do this later

once(fn)

Returns a new function that can be run multiple times, but makes sure fn is only run once.

var myFn = function () {
    console.log('Ran myFn');
};

var onceFn = Hoek.once(myFn);
onceFn(); // results in "Ran myFn"
onceFn(); // results in undefined

ignore

A simple no-op function. It does nothing at all.

Miscellaneous

uniqueFilename(path, extension)

path to prepend with the randomly generated file name. extension is the optional file extension, defaults to ''.

Returns a randomly generated file name at the specified path. The result is a fully resolved path to a file.

var result = Hoek.uniqueFilename('./test/modules', 'txt'); // results in "full/path/test/modules/{random}.txt"