How to get the first character of a string?

javascript

string-manipulation

unicode

browser-compatibility

byAnton Shumikhin·Aug 6, 2024

To swiftly fetch the first character of a string in JavaScript, utilize either str[0] or str.charAt(0).

Example:

// Knock knock...
let firstChar = "Hello"[0]; // Who's there? 'H'
// Or
let firstChar = "Hello".charAt(0); // 'H'arvey Dent, can we trust him?

These are the primary methods, but remember, context and requirements play a pivotal role in choosing the ideal one.

Decoding character access

Navigating through strings and fetching characters can be a labyrinth because of individual encodings and browser support variations. Here's a deeper look at these aspects.

Cross-browser compatibility and reliability

While str[0] offers brevity and modernity, it may be incompatible with older browsers like Internet Explorer 7. For wider user reach, consider str.charAt(0) or str.substring(0, 1).

Unicode characters and Array.from

In the world of Unicode characters or emojis, str[0] and charAt could act unpredictably by returning incomplete characters. Here, Array.from(str)[0] is your hero as it gracefully handles these scenarios.

Performance factors

If your project lives on the edge of performance, don't hesitate to trial and error with charAt, substring, and brackets, since their performance could waver across various JavaScript engines and browser versions.

Taking it up a notch

Let's examine some additional techniques to make our code a lot more robust.

Lesser known methods

string.slice(0, 1): Similar to substring, it has a good ratio of compatibility to performance.
string.substring(0, 1): Guards against potential Unicode issues and is your old browser's best bud.

Classic bugs and quick fixes

Be aware of a couple of common hiccups when dealing with complex strings, and know exactly how to squash those bugs:

Undefined: Older browsers might return undefined for string[0]. Use .charAt(0) to keep the bug at bay.
Unicode Surprises: Emojis or other symbols may return unexpected results with string[0] or string.charAt(0). Array.from(string)[0] or [...string][0] come to the rescue for such Unicode edge cases.

While these methods have seen consistent results, always test your code across different platforms to ensure a seamless user experience.

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