voca/ends_with.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');

/**
 * Checks whether `subject` ends with `end`.
 *
 * @function endsWith
 * @static
 * @since 1.0.0
 * @memberOf Query
 * @param {string} [subject=''] The string to verify.
 * @param {string} end The ending string.
 * @param {number} [position=subject.length] Search within `subject` as if the string were only `position` long.
 * @return {boolean} Returns `true` if `subject` ends with `end` or `false` otherwise.
 * @example
 * v.endsWith('red alert', 'alert');
 * // => true
 *
 * v.endsWith('metro south', 'metro');
 * // => false
 *
 * v.endsWith('Murphy', 'ph', 5);
 * // => true
 */

function endsWith(subject, end, position) {
  if (is_nil.isNil(end)) {
    return false;
  }

  var subjectString = coerce_to_string.coerceToString(subject);
  var endString = coerce_to_string.coerceToString(end);

  if (endString === '') {
    return true;
  }

  position = is_nil.isNil(position) ? subjectString.length : to_integer.clipNumber(to_integer.toInteger(position), 0, subjectString.length);
  position -= endString.length;
  var lastIndex = subjectString.indexOf(endString, position);
  return lastIndex !== -1 && lastIndex === position;
}

module.exports = endsWith;