sindresorhus / split-on-first

Split a string on the first occurrence of a given separator

split-on-first

Split a string on the first occurrence of a given separator

This is similar to String#split(), but that one splits on all the occurrences, not just the first one.

Install

$ npm install split-on-first

Usage

import splitOnFirst from 'split-on-first';

splitOnFirst('a-b-c', '-');
//=> ['a', 'b-c']

splitOnFirst('key:value:value2', ':');
//=> ['key', 'value:value2']

splitOnFirst('a---b---c', '---');
//=> ['a', 'b---c']

splitOnFirst('a-b-c', '+');
//=> []

splitOnFirst('abc', '');
//=> []

API

splitOnFirst(string, separator)

string

Type: string

The string to split.

separator

Type: string

The separator to split on.

Related

• split-at - Split a string at one or more indices

split-on-first's Issues

Non spec compliance

Using 'abc'.split(''), this value is given:

["a", "b", "c"]

But when using splitOnFirst('abc', ''), this expected result was not given:

["a", "bc"]

Instead, the value was:

["abc"]

IE 11 throws error due to use of reserved keyword (string) as function parameter

My app recently stopped working in IE 11, I tracked this down to a piece of your code that we are pulling in due to our use of the query-string module which uses split-on-first.

The issue is you're using a reserved keyword (string) as a function param here:

module.exports = (string, separator) => {
if (!(typeof string === 'string' && typeof separator === 'string')) {
throw new TypeError('Expected the arguments to be of type string');
}

While most modern browsers seem to be able to understand what the code really meant, not IE 11.
A simple fix would be changing string to str in this particular function

Update from CommonJS to ESM

Hi!

I would like to use query-string in a environment that doesn't support the old CommonJS,
it uses ESM since recently, but it still depends on split-on-first which does not.

Any chance of updating it?
A similar change was done recently for another dependency, which can be used as example: SamVerschueren/decode-uri-component#11

Thanks!

Arrow function should build into es5 before publish

https://github.com/sindresorhus/split-on-first/blob/master/index.js#L3

Regex support

Thoughts on regex support? indexOf would have to be replaced with search

const splitOnFirst = require('split-on-first');

splitOnFirst('a,b,c', /[.,]/);
//=> ['a', 'b,c']