voca/search.js

The ultimate JavaScript string library

'use strict';

var is_nil = require('./internal/is_nil.js');
require('./is_string.js');
var coerce_to_string = require('./internal/coerce_to_string.js');
var to_integer = require('./internal/to_integer.js');

/**
 * Returns the first index of a `pattern` match in `subject`.
 *
 * @function search
 * @static
 * @since 1.0.0
 * @memberOf Index
 * @param {string} [subject=''] The string where to search.
 * @param {string|RegExp} pattern The pattern to match. If `pattern` is not RegExp, it is transformed to `new RegExp(pattern)`.
 * @param {number} [fromIndex=0] The index to start searching.
 * @return {number} Returns the first match index or `-1` if not found.
 * @example
 * v.search('morning', /rn/);
 * // => 2
 *
 * v.search('evening', '/\d/');
 * // => -1
 */

function search(subject, pattern, fromIndex) {
  var subjectString = coerce_to_string.coerceToString(subject);
  var fromIndexNumber = is_nil.isNil(fromIndex) ? 0 : to_integer.clipNumber(to_integer.toInteger(fromIndex), 0, subjectString.length);
  var matchIndex = subjectString.substr(fromIndexNumber).search(pattern);

  if (matchIndex !== -1 && !isNaN(fromIndexNumber)) {
    matchIndex += fromIndexNumber;
  }

  return matchIndex;
}

module.exports = search;