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jQuery.map to iterate over objects with a .length property

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danheberden committed Mar 21, 2011
1 parent e38f074 commit d832f4f71ec51e67d4cae2557221ef582818f607
Showing with 27 additions and 25 deletions.
  1. +20 −20 src/core.js
  2. +7 −5 test/unit/core.js
@@ -704,33 +704,33 @@ jQuery.extend({
return ret;
},

// arg is for internal usage only
// arg is for internal usage only
map: function( elems, callback, arg ) {
var ret = [], value, i = 0,
length = elems.length,
// same object detection used in jQuery.each, not full-proof but very speedy.
isObj = length === undefined;

// the work for the loops - run elems[x] through callback
inLoop = function( key ) {
value = callback( elems[ key ], key, arg );

var value, ret = [],
i = 0,
length = elems.length,
// process .length if it's just an object member
isArray = length !== undefined && ( elems[ length - 1 ] || jQuery.isArray( elems ) );

// Go through the array, translating each of the items to their
// new value (or values).
if ( isArray ) {
for ( ; i < length; i++ ) {
value = callback( elems[ i ], i, arg );

if ( value != null ) {
ret[ ret.length ] = value;
}
}

// Go thorugh every key on the object
if ( isObj ) {
// Go thorugh every key on the object,
} else {
for ( key in elems ) {
inLoop( key );
}

// Go through the array, translating each of the items to their
// new value (or values).
} else {
for ( ; i < length; i++ ) {
inLoop( i );
value = callback( elems[ key ], key, arg );

if ( value != null ) {
ret[ ret.length ] = value;
}
}
}

@@ -608,7 +608,7 @@ test("first()/last()", function() {
});

test("map()", function() {
expect(6);
expect(7);

same(
jQuery("#ap").map(function(){
@@ -630,26 +630,28 @@ test("map()", function() {
var keys = jQuery.map( {a:1,b:2}, function( v, k ){
return k;
});

equals( keys.join(""), "ab", "Map the keys from a hash to an array" );

var values = jQuery.map( {a:1,b:2}, function( v, k ){
return v;
});

equals( values.join(""), "12", "Map the values from a hash to an array" );

// object with length prop
var values = jQuery.map( {a:1,b:2, length:3}, function( v, k ){
return v;
});
equals( values.join(""), "123", "Map the values from a hash with a length property to an array" );

var scripts = document.getElementsByTagName("script");
var mapped = jQuery.map( scripts, function( v, k ){
return v;
});

equals( mapped.length, scripts.length, "Map an array(-like) to a hash" );

var flat = jQuery.map( Array(4), function( v, k ){
return k % 2 ? k : [k,k,k];//try mixing array and regular returns
});

equals( flat.join(""), "00012223", "try the new flatten technique(#2616)" );
});

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