Transform

A substract of hapijs/hoek to be small enough for browserify

• Introduction
• Object
  • reach
  • transform
  • stringify
• Errors
  • assert

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.

A chain including negative numbers will work like negative indices on an array.

If chain is null, undefined or false, the object itself will be returned.

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

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

var chain = 'a.b.-1';
var obj = {a : {b : [2,3,6]}};

Hoek.reach(obj, chain); // returns 6

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. The first argument can also be an array of objects. In that case the method will return an array of transformed objects.

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'
// }

stringify(obj)

Converts an object to string using the built-in JSON.stringify() method with the difference that any errors are caught and reported back in the form of the returned string. Used as a shortcut for displaying information to the console (e.g. in error message) without the need to worry about invalid conversion.

var a = {};
a.b = a;
Hoek.stringify(a);    // Returns '[Cannot display object: Converting circular structure to JSON]'

Errors

assert(condition, message)

var a = 1, b = 2;

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

Note that you may also pass an already created Error object as the second parameter, and assert will throw that object.

var a = 1, b = 2;

Hoek.assert(a === b, new Error('a should equal b')); // Throws the given error object