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String

Lightweight namespace for string manipulation

API

Motivation​

globalThis.String functions and methods are very useful but has the following drawbacks :

  • Most functions are on the prototype
    • Since ESM, it creates a double syntax standard toDashCase(string) VS myString.toLowerCase()
    • String.prototype should never be extended
  • Some legacy design decisions
    • indexOf, lastIndexOf returns -1 when not found

String namespace corrects these problems in a pragmatic way :

  • Extendable : as an object String can be extends with a simple { ...String, myMethod() {} }
  • Uniform : every String function has a string as first parameter
  • Expressive : indexOf and lastIndexOf returns Option<Int>

Usage​

import { String, Option, Int } from '@w5s/core';

const baseName = (path: string): Option<string> => {
  const positionOption = String.lastIndexOf(expression, '/'); // Option<Int>;
  const afterLastSlash = Option.match(positionOption, (position) => ({
    None: () => path, // unchanged when not found
    Some: (position) => String.slice(path, position + 1), // everything after the last slash
  });
  return afterLastSlash;
}

Coding Guide​

tip

Prefer String functions over globalThis.String​

  • At best String will provide polyfill / better performance / better type safety
  • At worst String will call the native function

FAQ​