As hippietrail suggests, meder's answer can break surrogate pairs and misinterpret “characters.” For example:

// DO NOT USE THIS!
const a = '𝟘𝟙𝟚𝟛'.split('');
console.log(a);
// Output: ["�","�","�","�","�","�","�","�"]

I suggest using one of the following ES2015 features to correctly handle these character sequences.

Spread syntax (already answered by insertusernamehere)

const a = [...'𝟘𝟙𝟚𝟛'];
console.log(a);

Array.from

const a = Array.from('𝟘𝟙𝟚𝟛');
console.log(a);

RegExp u flag

const a = '𝟘𝟙𝟚𝟛'.split(/(?=[\s\S])/u);
console.log(a);

Use /(?=[\s\S])/u instead of /(?=.)/u because . does not match newlines. If you are still in ES5.1 era (or if your browser doesn't handle this regex correctly - like Edge), you can use the following alternative (transpiled by Babel). Note, that Babel tries to also handle unmatched surrogates correctly. However, this doesn't seem to work for unmatched low surrogates.

const a = '𝟘𝟙𝟚𝟛'.split(/(?=(?:[\0-\uD7FF\uE000-\uFFFF]|[\uD800-\uDBFF][\uDC00-\uDFFF]|\uD800-\uDBFF|(?:[^\uD800-\uDBFF]|^)[\uDC00-\uDFFF]))/);
console.log(a);

A for ... of ... loop

const s = '𝟘𝟙𝟚𝟛';
const a = [];
for (const s2 of s) {
   a.push(s2);
}
console.log(a);

You do it this way:

var str = s.join();