Split a String only on the First Occurrence of a Character

Split a String only on the First Occurrence of a Character #

To split a JavaScript string only on the first occurrence of a character, use the String.split() method with array destructuring to capture the first part and the remainder of the string in separate variables, e.g. const [first, ...rest] = str.split('-').

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const str = 'try-again-later';
const [first, ...rest] = str.split('-');

console.log(first); // 👉️ try
console.log(rest); // 👉️ ['again', 'later']

const remainder = rest.join('-');
console.log(remainder); // 👉️ again-later

In the code snippet, we've used the String.split method to split the string on a dash (-).

We use array destructuring assignment to assign the first element of the array to the first variable.

For the rest variable, we use both array destructuring and the rest operator to gather all of the remaining elements of the array into the rest variable.

At this point the rest variable is an array containing 2 elements - ['again', 'later'].

Finally we use the Array.join method to join the contents of the rest array on a dash and get the remainder of the string - again-later.

To split a JavaScript string only on the first occurrence of a character, call the slice() method on the string, passing it the index of the character + 1 as a parameter. The slice method will return the portion of the string after the first occurrence of the character.

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// ✅ Supported in IE
const str = 'try-again-later';

const after = str.slice(str.indexOf('-') + 1);
console.log(after); // 👉️ again-later

const before = str.slice(0, str.indexOf('-'));
console.log(before); // 👉️ try

The first example shows how to get the part after the last occurrence of a character.

The parameter we passed to the String.slice method is the start index - the index of the first character to be included in the new string.

The second example shows how to get the part before the first occurrence of the character.

The second parameter we passed to the slice() method is the end index - go up to, but not including this index.

In this scenario, we start at index 0 and go up to, but not including the index of the first occurrence of the supplied character.

Further Reading #

• Split a String at a specific Index using JavaScript
• How to Split a String by a Regex in JavaScript
• Split a String by Multiple Spaces in JavaScript
• Remove Special Characters from a String in JavaScript
• Check if String contains Special Characters in JavaScript
• Check if String starts with Substring in JavaScript
• Check if String ends with Substring in JavaScript