A tiny custom identity function creator for composable softwares.
import {createIdentity, identity, identitySecond, identityLast, identitySecondLast} from 'identitate';
// use built-in methods
console.log(identity('first', 'second', 'third', 'fourth', 'fifth')); // 'first'
console.log(identitySecond('first', 'second', 'third', 'fourth', 'fifth')); // 'second'
console.log(identityLast('first', 'second', 'third', 'fourth', 'fifth')); // 'fifth'
console.log(identitySecondLast('first', 'second', 'third', 'fourth', 'fifth')); // 'fourth'
// or create your own
const identityThird = createIdentity(2);
const identityThirdLast = createIdentity(-3);
const identityFirstNested = createIdentity(0, 'deeply[0].nested');
console.log(identityThird('first', 'second', 'third', 'fourth', 'fifth')); // 'third'
console.log(identityThirdLast('first', 'second', 'third', 'fourth', 'fifth')); // 'third'
console.log(identityFirstNested({deeply: [{nested: 'value'}]}, 'second', 'third', 'fourth', 'fifth')); // 'value'returns first argument passed to it
The classic identity function:
console.log(identity('first', 'second', 'third', 'fourth', 'fifth')); // 'first'returns second argument passed to it
console.log(identitySecond('first', 'second', 'third', 'fourth', 'fifth')); // 'second'Example usage when creating meta properties with the popular redux-actions package:
import {identity, identitySecond} from 'identitate';
import {createAction} from 'redux-actions';
export const doThing = createAction('DO_THING', identity, identitySecond);
console.log(doThing('payload', 'meta')); // {meta: 'meta', payload: 'payload', type: 'DO_THING'}returns last argument passed to it, regardless of total number of arguments
console.log(identityLast('first', 'second', 'third', 'fourth', 'fifth')); // 'fifth'
console.log(identityLast('first', 'second', 'third')); // 'third'returns second-to-last argument passed to it, regardless of total number of arguments
console.log(identitySecondLast('first', 'second', 'third', 'fourth', 'fifth')); // 'fourth'
console.log(identitySecondLast('first', 'second', 'third')); // 'second'creates a new identity method based on the parameters passed
createIdentity(position: number[, path: (Array<number|string>|number|string)]): any
// use a positive number to get the index of the arguments (zero-indexed)
const identityFourth = createIdentity(3);
console.log(identityLast('first', 'second', 'third', 'fourth', 'fifth')); // 'fourth'
// use a negative number to get the index of the arguments relative to the last
const identityThirdLast = createIdentity(-3);
console.log(identityLast('first', 'second', 'third', 'fourth', 'fifth')); // 'third'
// include a path to get the deeply-nested value of that argument
const identityNested = createIdentity(0, 'deeply.nested');
console.log(identityNested({deeply: {nested: 'value'}})); // 'value'The path parameter uses pathington under the hood for path parsing, so check there for valid values.
- Chrome (all versions)
- Firefox (all versions)
- Edge (all versions)
- Opera 15+
- IE 9+
- Safari 6+
- iOS 8+
- Android 4+
Standard stuff, clone the repo and npm install dependencies. The npm scripts available:
build=> run webpack to build developmentdistfile with NODE_ENV=developmentbuild:minified=> run webpack to build productiondistfile with NODE_ENV=productiondev=> run webpack dev server to run example app / playgrounddist=> runsbuildandbuild-minifiedlint=> run ESLint against all files in thesrcfolderprepublish=> runscompile-for-publishprepublish:compile=> runlint,test:coverage,transpile:es,transpile:lib,disttest=> run AVA test functions withNODE_ENV=testtest:coverage=> runtestbut withnycfor coverage checkertest:watch=> runtest, but with persistent watchertranspile:lib=> run babel against all files insrcto create files inlibtranspile:es=> run babel against all files insrcto create files ines, preserving ES2015 modules (forpkg.module)