toPairs

Returns pairs of (key, value) for all own enumerable properties in an object.

Example:

const toPairs = require('folktale/core/object/to-pairs');

const pair = { x: 10, y: 20 };
toPairs(pair);
// ==> [['x', 10], ['y', 20]]
// (in ES5- VMs this may be [['y', 20], ['x', 10]])

Why?

Objects in JavaScript are commonly used as dictionaries, but natively there are no operations to work with them in that way. This function allows one to extract the (key, value) pairs from an object:

const toPairs = require('folktale/core/object/to-pairs');

const pair = { x: 10, y: 20 };
toPairs(pair);
// ==> [['x', 10], ['y', 20]]
// or  [['y', 20], ['x', 10]]

Inherited properties, and those that are not marked as enumerable, are not returned in the resulting array:

const p1 = { z: 2 };
const pair2 = Object.create(p1);
pair2.x = 10; pair2.y = 20;

toPairs(pair2);
// ==> [['x', 10], ['y', 20]]
// or  [['y', 20], ['x', 10]]

// non-enumerable property x
Object.defineProperty(p1, 'x', { value: 1 });

toPairs(p1);
// ==> [['z', 2]]

Caveats

While ECMAScript 2015 specifies that objects are ordered using insertion order, you're not guaranteed to get that behaviour in any non-ES2015 engine, so for all effects it's better to treat the result of this operation as an unordered collection.