simple template function

template.js

export function isFunction(arg) {
    return typeof arg === 'function';
}
const cachedKeys = new Map();
/**
 * Get data by key
 * const data = {age: {value: 9}};
 * getData(data, 'age.value') => 9
 * getData(data, 'age.buzz') => 'age.buzz'
 *
 * @param {object} data
 * @param {string} originKey
 * @returns {string}
 */
function getData(data, originKey) {
    if (typeof data !== 'object') {
        return originKey;
    }
    const keys = cachedKeys.get(originKey) || originKey.replace(/([^a-zA-Z_.]+)/g, '').split('.');
    let result = originKey;
    for (const key of keys) {
        if (key in data) {
            result = data[key];
            data = data[key];
            continue;
        }
        result = originKey;
        break;
    }
    return isFunction(result) ? result() : result;
}
/**
 * Simple template string
 *
 * @example
 *
 * const str = 'My name is ${name}, and is ${age}, ${girlName} is my girl friend';
 * const data = {name: 'Buzz', age: 'young man'};
 * // result = 'My name is Buzz, and is young man, ${girlName} is my girl friend';
 *
 * @param {string} str
 * @param {object} params
 * @returns {string}
 */
export function template(str, params) {
    if (!params) { // falsy value
        return str;
    }
    return str.replace(/\${([a-zA-Z_.]+)}/g, (substring) => getData(params, substring));
}

template.ts

export function isFunction(arg: any): arg is Function {
  return typeof arg === 'function';
}

const cachedKeys: Map<string, string> = new Map();

/**
 * Get data by key
 * const data = {age: {value: 9}};
 * getData(data, 'age.value') => 9
 * getData(data, 'age.buzz') => 'age.buzz'
 *
 * @param {object} data
 * @param {string} originKey
 * @returns {string}
 */
function getData(data: any, originKey: string): string {
  if (typeof data !== 'object') {
    return originKey;
  }

  const keys = cachedKeys.get(originKey) || originKey.replace(/([^a-zA-Z_.]+)/g, '').split('.');
  let result: string | Function = originKey;

  for (const key of keys) {
    if (key in data) {
      result = data[key];
      data = data[key];
      continue;
    }
    result = originKey;
    break;
  }

  return isFunction(result) ? result() : result;
}

/**
 * Simple template string
 *
 * @example
 *
 * const str = 'My name is ${name}, and is ${age}, ${girlName} is my girl friend';
 * const data = {name: 'Buzz', age: 'young man'};
 * // result = 'My name is Buzz, and is young man, ${girlName} is my girl friend';
 *
 * @param {string} str
 * @param {object} params
 * @returns {string}
 */
export function template(str: string, params: any): string {
  if (!params) { // falsy value
    return str;
  }
  return str.replace(/\${([a-zA-Z_.]+)}/g, (substring: string) => getData(params, substring));
}