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Add fromIndex to _.indexOf and _.lastIndexOf. [closes #20]

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Former-commit-id: 3ab67c318a5a7fc2e521a9a2573b694e6920b14d
This commit is contained in:
John-David Dalton
2012-05-31 17:23:45 -06:00
parent 861eea5148
commit 3d8cc32302
2 changed files with 106 additions and 20 deletions
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57
lodash.js
View File

@@ -1077,6 +1077,9 @@
*
* _.sortBy([1, 2, 3, 4, 5, 6], function(num) { return this.sin(num); }, Math);
* // => [5, 4, 6, 3, 1, 2]
*
* _.sortBy(['larry', 'brendan', 'moe'], 'length');
* // => ['moe', 'larry', 'brendan']
*/
function sortBy(array, callback, thisArg) {
if (toString.call(callback) != funcClass) {
@@ -1114,23 +1117,33 @@
* @category Arrays
* @param {Array} array The array to search.
* @param {Mixed} value The value to search for.
* @param {Boolean} [isSorted=false] A flag to indicate that the `array` is already sorted.
* @param {Boolean|Number} [fromIndex=0] The index to start searching from or
* `true` to perform a binary search on a sorted `array`.
* @returns {Number} Returns the index of the matched value or `-1`.
* @example
*
* _.indexOf([1, 2, 3], 2);
* _.indexOf([1, 2, 3, 1, 2, 3], 2);
* // => 1
*
* _.indexOf([1, 2, 3, 1, 2, 3], 2, 3);
* // => 4
*
* _.indexOf([1, 1, 2, 2, 3, 3], 2, true);
* // => 2
*/
function indexOf(array, value, isSorted) {
var index, length;
if (!array) {
return -1;
function indexOf(array, value, fromIndex) {
var index = -1,
length = array.length;
if (fromIndex) {
if (fromIndex === +fromIndex) {
index = (fromIndex < 0 ? Math.max(0, length + fromIndex) : fromIndex) - 1;
} else {
index = sortedIndex(array, value);
return array[index] === value ? index : -1;
}
}
if (isSorted) {
index = sortedIndex(array, value);
return array[index] === value ? index : -1;
}
for (index = 0, length = array.length; index < length; index++) {
while (++index < length) {
if (array[index] === value) {
return index;
}
@@ -1250,17 +1263,21 @@
* @category Arrays
* @param {Array} array The array to search.
* @param {Mixed} value The value to search for.
* @param {Number} [fromIndex=array.length-1] The index to start searching from.
* @returns {Number} Returns the index of the matched value or `-1`.
* @example
*
* _.lastIndexOf([1, 2, 3, 1, 2, 3], 2);
* // => 4
*
* _.lastIndexOf([1, 2, 3, 1, 2, 3], 2, 3);
* // => 1
*/
function lastIndexOf(array, value) {
if (!array) {
return -1;
}
function lastIndexOf(array, value, fromIndex) {
var index = array.length;
if (fromIndex && fromIndex === +fromIndex) {
index = (fromIndex < 0 ? Math.max(0, index + fromIndex) : Math.min(fromIndex, index - 1)) + 1;
}
while (index--) {
if (array[index] === value) {
return index;
@@ -1465,10 +1482,10 @@
}
/**
* Uses a binary search to determine the smallest index at which the `value`
* should be inserted into the `collection` in order to maintain the sort order
* of the `collection`. If `callback` is passed, it will be executed for each
* value in the `collection` to compute their sort ranking. The `callback` is
* Uses a binary search to determine the smallest index at which the `value`
* should be inserted into the `array` in order to maintain the sort order
* of the `array`. If `callback` is passed, it will be executed for each
* value in the `array` to compute their sort ranking. The `callback` is
* invoked with 1 argument; (value).
*
* @static
@@ -1478,7 +1495,7 @@
* @param {Mixed} value The value to evaluate.
* @param {Function} [callback] The function called per iteration.
* @returns {Number} Returns the index at which the value should be inserted
* into the collection.
* into the array.
* @example
*
* _.sortedIndex([10, 20, 30, 40, 50], 35);

69
test/test.js
View File

@@ -254,6 +254,42 @@
/*--------------------------------------------------------------------------*/
QUnit.module('lodash.indexOf');
(function() {
var array = [1, 2, 3, 1, 2, 3];
test('should work with a positive `fromIndex`', function() {
equal(_.indexOf(array, 1, 2), 3);
});
test('should work with `fromIndex` >= `array.length`', function() {
equal(_.indexOf(array, 1, 6), -1);
equal(_.indexOf(array, undefined, 6), -1);
equal(_.indexOf(array, 1, 8), -1);
equal(_.indexOf(array, undefined, 8), -1);
});
test('should work with a negative `fromIndex`', function() {
equal(_.indexOf(array, 2, -3), 4);
});
test('should work with a negative `fromIndex` <= `-array.length`', function() {
equal(_.indexOf(array, 1, -6), 0);
equal(_.indexOf(array, 2, -8), 1);
});
test('should ignore non-number `fromIndex` values', function() {
equal(_.indexOf([1, 2, 3], 1, '1'), 0);
});
test('should work with `isSorted`', function() {
equal(_.indexOf([1, 2, 3], 1, true), 0);
});
}());
/*--------------------------------------------------------------------------*/
QUnit.module('lodash.initial');
(function() {
@@ -324,6 +360,39 @@
/*--------------------------------------------------------------------------*/
QUnit.module('lodash.lastIndexOf');
(function() {
var array = [1, 2, 3, 1, 2, 3];
test('should work with a positive `fromIndex`', function() {
equal(_.lastIndexOf(array, 1, 2), 0);
});
test('should work with `fromIndex` >= `array.length`', function() {
equal(_.lastIndexOf(array, undefined, 6), -1);
equal(_.lastIndexOf(array, 1, 6), 3);
equal(_.lastIndexOf(array, undefined, 8), -1);
equal(_.lastIndexOf(array, 1, 8), 3);
});
test('should work with a negative `fromIndex`', function() {
equal(_.lastIndexOf(array, 2, -3), 1);
});
test('should work with a negative `fromIndex` <= `-array.length`', function() {
equal(_.lastIndexOf(array, 1, -6), 0);
equal(_.lastIndexOf(array, 2, -8), -1);
});
test('should ignore non-number `fromIndex` values', function() {
equal(_.lastIndexOf([1, 2, 3], 3, '1'), 2);
equal(_.lastIndexOf([1, 2, 3], 3, true), 2);
});
}());
/*--------------------------------------------------------------------------*/
QUnit.module('lodash.partial');
(function() {