foreach-prop

foreach-prop

Array-like methods for objects

Install

npm install foreach-prop

Methods

forEach

similar to Array.prototype.forEach. It executes the provided callback function for every key-value-pair in the object. Once iniciated there is no way to stop the execution of this function, if you intend to stop the iteration at some point have a look at findKey method.

forEach(object, function callback(value, key, ...extra) => void, ...extra): void;

The callback function inherits the this value from the function call, so if you want a specific this value in your callback function, you can call it using the call method of the Function.prototype...

forEach.call(thisArg, object, callback, ...extra);

map

similar to Array.prototype.map. It executes the provided callback function for every key-value-pair in the object and returns a new object.

map(object, function callback(value, key, ...extra) => any, ...extra): object;

The callback function inherits the this value from the function call, so if you want a specific this value in your callback function, you can call it using the call method of the Function.prototype...

map.call(thisArg, object, callback, ...extra);

keyOf

similar to Array.prototype.indexOf. It returns the key of the first value that equals the provided one.

keyOf(object, value): string;

lastKeyOf

similar to Array.prototype.lastIndexOf. It returns the key of the last value that equals the provided one.

lastKeyOf(object, value): string;

findKey

similar to Array.prototype.findIndex. It executes the provided callback function for every key-value-pair in the object and returns the key once the provided callback function return a truthy value. It returns null if nothing found.

findKey(object, function callback(value, key, ...extra) => any, ...extra): string;

The callback function inherits the this value from the function call, so if you want a specific this value in your callback function, you can call it using the call method of the Function.prototype...

findKey.call(thisArg, object, callback, ...extra);

find

similar to Array.prototype.find. It executes the provided callback function for every key-value-pair in the object and returns the value once the provided callback function return a truthy value. It returns undefined if nothing found.

find(object, function callback(value, key, ...extra) => any, ...extra): any;

Note that the returned value may be undefined even if the condition is met and the value is undefined.

const something; // something is undefined
const value = find({ something }, (val, key) => (key === "something"));
console.log(value); // it logs undefined because something is undefined

The callback function inherits the this value from the function call, so if you want a specific this value in your callback function, you can call it using the call method of the Function.prototype...

find.call(thisArg, object, callback, ...extra);

filter

similar to Array.prototype.filter. It executes the provided callback function for every key-value-pair in the object and returns a new object containing the key-value-pairs corresponding to those where the provided callback function returned a truthy value.

filter(object, function callback(value, key, ...extra) => any, ...extra): object;

The callback function inherits the this value from the function call, so if you want a specific this value in your callback function, you can call it using the call method of the Function.prototype...

filter.call(thisArg, object, callback, ...extra);

reduce

similar to Array.prototype.reduce but with a major difference: if no initial value provided it defaults to undefined.

reduce(object, function callback(current, value, key, ...extra) => any, initial, ...extra): any;

The callback function inherits the this value from the function call, so if you want a specific this value in your callback function, you can call it using the call method of the Function.prototype...

reduce.call(thisArg, object, callback, initial, ...extra);

License

MIT License