lodash.range/index.js

/**
 * lodash (Custom Build) <https://lodash.com/>
 * Build: `lodash modularize exports="npm" -o ./`
 * Copyright jQuery Foundation and other contributors <https://jquery.org/>
 * Released under MIT license <https://lodash.com/license>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 */

/** Used as references for various `Number` constants. */
var INFINITY = 1 / 0,
    MAX_SAFE_INTEGER = 9007199254740991,
    MAX_INTEGER = 1.7976931348623157e+308,
    NAN = 0 / 0;

/** `Object#toString` result references. */
var funcTag = '[object Function]',
    genTag = '[object GeneratorFunction]',
    symbolTag = '[object Symbol]';

/** Used to match leading and trailing whitespace. */
var reTrim = /^\s+|\s+$/g;

/** Used to detect bad signed hexadecimal string values. */
var reIsBadHex = /^[-+]0x[0-9a-f]+$/i;

/** Used to detect binary string values. */
var reIsBinary = /^0b[01]+$/i;

/** Used to detect octal string values. */
var reIsOctal = /^0o[0-7]+$/i;

/** Used to detect unsigned integer values. */
var reIsUint = /^(?:0|[1-9]\d*)$/;

/** Built-in method references without a dependency on `root`. */
var freeParseInt = parseInt;

/**
 * The base implementation of `_.property` without support for deep paths.
 *
 * @private
 * @param {string} key The key of the property to get.
 * @returns {Function} Returns the new accessor function.
 */
function baseProperty(key) {
  return function(object) {
    return object == null ? undefined : object[key];
  };
}

/** Used for built-in method references. */
var objectProto = Object.prototype;

/**
 * Used to resolve the
 * [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
 * of values.
 */
var objectToString = objectProto.toString;

/* Built-in method references for those with the same name as other `lodash` methods. */
var nativeCeil = Math.ceil,
    nativeMax = Math.max;

/**
 * The base implementation of `_.range` and `_.rangeRight` which doesn't
 * coerce arguments.
 *
 * @private
 * @param {number} start The start of the range.
 * @param {number} end The end of the range.
 * @param {number} step The value to increment or decrement by.
 * @param {boolean} [fromRight] Specify iterating from right to left.
 * @returns {Array} Returns the range of numbers.
 */
function baseRange(start, end, step, fromRight) {
  var index = -1,
      length = nativeMax(nativeCeil((end - start) / (step || 1)), 0),
      result = Array(length);

  while (length--) {
    result[fromRight ? length : ++index] = start;
    start += step;
  }
  return result;
}

/**
 * Creates a `_.range` or `_.rangeRight` function.
 *
 * @private
 * @param {boolean} [fromRight] Specify iterating from right to left.
 * @returns {Function} Returns the new range function.
 */
function createRange(fromRight) {
  return function(start, end, step) {
    if (step && typeof step != 'number' && isIterateeCall(start, end, step)) {
      end = step = undefined;
    }
    // Ensure the sign of `-0` is preserved.
    start = toFinite(start);
    if (end === undefined) {
      end = start;
      start = 0;
    } else {
      end = toFinite(end);
    }
    step = step === undefined ? (start < end ? 1 : -1) : toFinite(step);
    return baseRange(start, end, step, fromRight);
  };
}

/**
 * Gets the "length" property value of `object`.
 *
 * **Note:** This function is used to avoid a
 * [JIT bug](https://bugs.webkit.org/show_bug.cgi?id=142792) that affects
 * Safari on at least iOS 8.1-8.3 ARM64.
 *
 * @private
 * @param {Object} object The object to query.
 * @returns {*} Returns the "length" value.
 */
var getLength = baseProperty('length');

/**
 * Checks if `value` is a valid array-like index.
 *
 * @private
 * @param {*} value The value to check.
 * @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index.
 * @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
 */
function isIndex(value, length) {
  length = length == null ? MAX_SAFE_INTEGER : length;
  return !!length &&
    (typeof value == 'number' || reIsUint.test(value)) &&
    (value > -1 && value % 1 == 0 && value < length);
}

/**
 * Checks if the given arguments are from an iteratee call.
 *
 * @private
 * @param {*} value The potential iteratee value argument.
 * @param {*} index The potential iteratee index or key argument.
 * @param {*} object The potential iteratee object argument.
 * @returns {boolean} Returns `true` if the arguments are from an iteratee call,
 *  else `false`.
 */
function isIterateeCall(value, index, object) {
  if (!isObject(object)) {
    return false;
  }
  var type = typeof index;
  if (type == 'number'
        ? (isArrayLike(object) && isIndex(index, object.length))
        : (type == 'string' && index in object)
      ) {
    return eq(object[index], value);
  }
  return false;
}

/**
 * Performs a
 * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
 * comparison between two values to determine if they are equivalent.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to compare.
 * @param {*} other The other value to compare.
 * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
 * @example
 *
 * var object = { 'a': 1 };
 * var other = { 'a': 1 };
 *
 * _.eq(object, object);
 * // => true
 *
 * _.eq(object, other);
 * // => false
 *
 * _.eq('a', 'a');
 * // => true
 *
 * _.eq('a', Object('a'));
 * // => false
 *
 * _.eq(NaN, NaN);
 * // => true
 */
function eq(value, other) {
  return value === other || (value !== value && other !== other);
}

/**
 * Checks if `value` is array-like. A value is considered array-like if it's
 * not a function and has a `value.length` that's an integer greater than or
 * equal to `0` and less than or equal to `Number.MAX_SAFE_INTEGER`.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is array-like, else `false`.
 * @example
 *
 * _.isArrayLike([1, 2, 3]);
 * // => true
 *
 * _.isArrayLike(document.body.children);
 * // => true
 *
 * _.isArrayLike('abc');
 * // => true
 *
 * _.isArrayLike(_.noop);
 * // => false
 */
function isArrayLike(value) {
  return value != null && isLength(getLength(value)) && !isFunction(value);
}

/**
 * Checks if `value` is classified as a `Function` object.
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a function, else `false`.
 * @example
 *
 * _.isFunction(_);
 * // => true
 *
 * _.isFunction(/abc/);
 * // => false
 */
function isFunction(value) {
  // The use of `Object#toString` avoids issues with the `typeof` operator
  // in Safari 8 which returns 'object' for typed array and weak map constructors,
  // and PhantomJS 1.9 which returns 'function' for `NodeList` instances.
  var tag = isObject(value) ? objectToString.call(value) : '';
  return tag == funcTag || tag == genTag;
}

/**
 * Checks if `value` is a valid array-like length.
 *
 * **Note:** This function is loosely based on
 * [`ToLength`](http://ecma-international.org/ecma-262/6.0/#sec-tolength).
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a valid length,
 *  else `false`.
 * @example
 *
 * _.isLength(3);
 * // => true
 *
 * _.isLength(Number.MIN_VALUE);
 * // => false
 *
 * _.isLength(Infinity);
 * // => false
 *
 * _.isLength('3');
 * // => false
 */
function isLength(value) {
  return typeof value == 'number' &&
    value > -1 && value % 1 == 0 && value <= MAX_SAFE_INTEGER;
}

/**
 * Checks if `value` is the
 * [language type](http://www.ecma-international.org/ecma-262/6.0/#sec-ecmascript-language-types)
 * of `Object`. (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is an object, else `false`.
 * @example
 *
 * _.isObject({});
 * // => true
 *
 * _.isObject([1, 2, 3]);
 * // => true
 *
 * _.isObject(_.noop);
 * // => true
 *
 * _.isObject(null);
 * // => false
 */
function isObject(value) {
  var type = typeof value;
  return !!value && (type == 'object' || type == 'function');
}

/**
 * Checks if `value` is object-like. A value is object-like if it's not `null`
 * and has a `typeof` result of "object".
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is object-like, else `false`.
 * @example
 *
 * _.isObjectLike({});
 * // => true
 *
 * _.isObjectLike([1, 2, 3]);
 * // => true
 *
 * _.isObjectLike(_.noop);
 * // => false
 *
 * _.isObjectLike(null);
 * // => false
 */
function isObjectLike(value) {
  return !!value && typeof value == 'object';
}

/**
 * Checks if `value` is classified as a `Symbol` primitive or object.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a symbol, else `false`.
 * @example
 *
 * _.isSymbol(Symbol.iterator);
 * // => true
 *
 * _.isSymbol('abc');
 * // => false
 */
function isSymbol(value) {
  return typeof value == 'symbol' ||
    (isObjectLike(value) && objectToString.call(value) == symbolTag);
}

/**
 * Converts `value` to a finite number.
 *
 * @static
 * @memberOf _
 * @since 4.12.0
 * @category Lang
 * @param {*} value The value to convert.
 * @returns {number} Returns the converted number.
 * @example
 *
 * _.toFinite(3.2);
 * // => 3.2
 *
 * _.toFinite(Number.MIN_VALUE);
 * // => 5e-324
 *
 * _.toFinite(Infinity);
 * // => 1.7976931348623157e+308
 *
 * _.toFinite('3.2');
 * // => 3.2
 */
function toFinite(value) {
  if (!value) {
    return value === 0 ? value : 0;
  }
  value = toNumber(value);
  if (value === INFINITY || value === -INFINITY) {
    var sign = (value < 0 ? -1 : 1);
    return sign * MAX_INTEGER;
  }
  return value === value ? value : 0;
}

/**
 * Converts `value` to a number.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to process.
 * @returns {number} Returns the number.
 * @example
 *
 * _.toNumber(3.2);
 * // => 3.2
 *
 * _.toNumber(Number.MIN_VALUE);
 * // => 5e-324
 *
 * _.toNumber(Infinity);
 * // => Infinity
 *
 * _.toNumber('3.2');
 * // => 3.2
 */
function toNumber(value) {
  if (typeof value == 'number') {
    return value;
  }
  if (isSymbol(value)) {
    return NAN;
  }
  if (isObject(value)) {
    var other = isFunction(value.valueOf) ? value.valueOf() : value;
    value = isObject(other) ? (other + '') : other;
  }
  if (typeof value != 'string') {
    return value === 0 ? value : +value;
  }
  value = value.replace(reTrim, '');
  var isBinary = reIsBinary.test(value);
  return (isBinary || reIsOctal.test(value))
    ? freeParseInt(value.slice(2), isBinary ? 2 : 8)
    : (reIsBadHex.test(value) ? NAN : +value);
}

/**
 * Creates an array of numbers (positive and/or negative) progressing from
 * `start` up to, but not including, `end`. A step of `-1` is used if a negative
 * `start` is specified without an `end` or `step`. If `end` is not specified,
 * it's set to `start` with `start` then set to `0`.
 *
 * **Note:** JavaScript follows the IEEE-754 standard for resolving
 * floating-point values which can produce unexpected results.
 *
 * @static
 * @since 0.1.0
 * @memberOf _
 * @category Util
 * @param {number} [start=0] The start of the range.
 * @param {number} end The end of the range.
 * @param {number} [step=1] The value to increment or decrement by.
 * @returns {Array} Returns the range of numbers.
 * @see _.inRange, _.rangeRight
 * @example
 *
 * _.range(4);
 * // => [0, 1, 2, 3]
 *
 * _.range(-4);
 * // => [0, -1, -2, -3]
 *
 * _.range(1, 5);
 * // => [1, 2, 3, 4]
 *
 * _.range(0, 20, 5);
 * // => [0, 5, 10, 15]
 *
 * _.range(0, -4, -1);
 * // => [0, -1, -2, -3]
 *
 * _.range(1, 4, 0);
 * // => [1, 1, 1]
 *
 * _.range(0);
 * // => []
 */
var range = createRange();

module.exports = range;