Formatter for cut string in the middle

cutOnMiddle.ts

import { TCutOnMiddleArgs } from './types';

/**
 * compare first and second number
 * @param firstLength number of cut result
 * @param secondLength number of base string
 * @returns boolean
 */
const shouldBeCut = (firstLength: number = 0, secondLength: number) => {
  return firstLength < secondLength;
};

/**
 * function cut string in the middle and insert placeholder between first and last counts
 * Default Values:
 *  - `firstCount` -> 6
 *  - `lastCount` -> 3
 *  - `placeholder` -> ...
 *
 * @example
 * const formatted = cutOnMiddle({ value: '12345678901234' }) // output: 123456...432
 *
 * @example
 * const formatted = cutOnMiddle({ value: 'QWERTY', firstCount: 1, lastCount: 1 })
 * // output: Q...Y
 *
 * @returns formatted string
 */
export const cutOnMiddle = ({
  value,
  firstCount = 6,
  lastCount = 3,
  placeholder = '...',
}: TCutOnMiddleArgs) => {
  if (!value?.length) {
    return value;
  }

  const cutLength = firstCount + lastCount + placeholder.length;
  const isShouldBeCut = shouldBeCut(cutLength, value?.length);

  if (!isShouldBeCut) {
    return value;
  }

  return (
    value.slice(0, firstCount) +
    placeholder +
    value.slice(value.length - lastCount)
  );
};

types.ts

export type TCutOnMiddleArgs = {
  value: string;
  firstCount?: number;
  lastCount?: number;
  placeholder?: string;
};

/**
 * args for formatting strings and numbers with passed regex
 */
export type TFormatWithRegexArgs = {
  /**
   * value to prepare
   */
  value: string | number;
  /**
   * regex for search
   */
  regex: RegExp | string;
  /**
   * string for replacing serched values
   */
  replaceValue: string;
};