isDigit

The isDigit function checks if a character is a digit (0-9).

Basic Usage

import { isDigit } from "cx/util";

isDigit("5"); // true
isDigit("0"); // true
isDigit("9"); // true
isDigit("a"); // false
isDigit(" "); // false
isDigit(""); // false

Common Use Cases

Input Validation

import { isDigit } from "cx/util";

function isNumericString(str: string): boolean {
  for (const char of str) {
    if (!isDigit(char)) return false;
  }
  return str.length > 0;
}

isNumericString("12345"); // true
isNumericString("123a5"); // false

Character Filtering

import { isDigit } from "cx/util";

function extractDigits(str: string): string {
  return str.split("").filter(isDigit).join("");
}

extractDigits("abc123def456"); // "123456"
extractDigits("Phone: (555) 123-4567"); // "5551234567"

Parsing

import { isDigit } from "cx/util";

function parseLeadingNumber(str: string): number | null {
  let numStr = "";
  for (const char of str) {
    if (isDigit(char)) {
      numStr += char;
    } else {
      break;
    }
  }
  return numStr ? parseInt(numStr, 10) : null;
}

parseLeadingNumber("123abc"); // 123
parseLeadingNumber("abc123"); // null

API

function isDigit(x: any): boolean;

Returns: true if the value is a single digit character (‘0’-‘9’).