我有一个JavaScript对象数组：
var objs = [
{ first_nom: 'Lazslo', last_nom: 'Jamf' },
{ first_nom: 'Pig', last_nom: 'Bodine' },
{ first_nom: 'Pirate', last_nom: 'Prentice' }
];
如何在JavaScript中按last_nom的值对它们进行排序？
我知道排序（a，b），但这似乎只适用于字符串和数字。是否需要向对象添加toString（）方法？
当前回答
您也可以使用自定义toString（）方法（由默认比较函数调用）创建对象类型，而不是使用自定义比较函数：
function Person(firstName, lastName) {
this.firtName = firstName;
this.lastName = lastName;
}
Person.prototype.toString = function() {
return this.lastName + ', ' + this.firstName;
}
var persons = [ new Person('Lazslo', 'Jamf'), ...]
persons.sort();
其他回答
编写自己的比较函数非常简单：
function compare( a, b ) {
if ( a.last_nom < b.last_nom ){
return -1;
}
if ( a.last_nom > b.last_nom ){
return 1;
}
return 0;
}
objs.sort( compare );
或内联（由Marco Demaio转交）：
objs.sort((a,b) => (a.last_nom > b.last_nom) ? 1 : ((b.last_nom > a.last_nom) ? -1 : 0))
或简化为数字（由Andre Figueiredo转交）：
objs.sort((a,b) => a.last_nom - b.last_nom); // b - a for reverse sort
在ES6/ES2015或更高版本中，您可以这样做：
objs.sort((a, b) => a.last_nom.localeCompare(b.last_nom));
ES6/ES2015之前
objs.sort(function(a, b) {
return a.last_nom.localeCompare(b.last_nom)
});
您可能需要将它们转换为小写形式，以防止混淆。
objs.sort(function (a, b) {
var nameA = a.last_nom.toLowerCase(), nameB = b.last_nom.toLowerCase()
if (nameA < nameB)
return -1;
if (nameA > nameB)
return 1;
return 0; // No sorting
})
我没有看到任何类似于我的实现。此版本基于施瓦茨变换习惯用法。
function sortByAttribute(array, ...attrs) {
// Generate an array of predicate-objects containing
// property getter, and descending indicator
let predicates = attrs.map(pred => {
let descending = pred.charAt(0) === '-' ? -1 : 1;
pred = pred.replace(/^-/, '');
return {
getter: o => o[pred],
descend: descending
};
});
// Schwartzian transform idiom implementation. AKA "decorate-sort-undecorate"
return array.map(item => {
return {
src: item,
compareValues: predicates.map(predicate => predicate.getter(item))
};
})
.sort((o1, o2) => {
let i = -1, result = 0;
while (++i < predicates.length) {
if (o1.compareValues[i] < o2.compareValues[i])
result = -1;
if (o1.compareValues[i] > o2.compareValues[i])
result = 1;
if (result *= predicates[i].descend)
break;
}
return result;
})
.map(item => item.src);
}
下面是如何使用它的示例：
let games = [
{ name: 'Mashraki', rating: 4.21 },
{ name: 'Hill Climb Racing', rating: 3.88 },
{ name: 'Angry Birds Space', rating: 3.88 },
{ name: 'Badland', rating: 4.33 }
];
// Sort by one attribute
console.log(sortByAttribute(games, 'name'));
// Sort by mupltiple attributes
console.log(sortByAttribute(games, '-rating', 'name'));
使用xPrototype的sortBy：
var o = [
{ Name: 'Lazslo', LastName: 'Jamf' },
{ Name: 'Pig', LastName: 'Bodine' },
{ Name: 'Pirate', LastName: 'Prentice' },
{ Name: 'Pag', LastName: 'Bodine' }
];
// Original
o.each(function (a, b) { console.log(a, b); });
/*
0 Object {Name: "Lazslo", LastName: "Jamf"}
1 Object {Name: "Pig", LastName: "Bodine"}
2 Object {Name: "Pirate", LastName: "Prentice"}
3 Object {Name: "Pag", LastName: "Bodine"}
*/
// Sort By LastName ASC, Name ASC
o.sortBy('LastName', 'Name').each(function(a, b) { console.log(a, b); });
/*
0 Object {Name: "Pag", LastName: "Bodine"}
1 Object {Name: "Pig", LastName: "Bodine"}
2 Object {Name: "Lazslo", LastName: "Jamf"}
3 Object {Name: "Pirate", LastName: "Prentice"}
*/
// Sort by LastName ASC and Name ASC
o.sortBy('LastName'.asc, 'Name'.asc).each(function(a, b) { console.log(a, b); });
/*
0 Object {Name: "Pag", LastName: "Bodine"}
1 Object {Name: "Pig", LastName: "Bodine"}
2 Object {Name: "Lazslo", LastName: "Jamf"}
3 Object {Name: "Pirate", LastName: "Prentice"}
*/
// Sort by LastName DESC and Name DESC
o.sortBy('LastName'.desc, 'Name'.desc).each(function(a, b) { console.log(a, b); });
/*
0 Object {Name: "Pirate", LastName: "Prentice"}
1 Object {Name: "Lazslo", LastName: "Jamf"}
2 Object {Name: "Pig", LastName: "Bodine"}
3 Object {Name: "Pag", LastName: "Bodine"}
*/
// Sort by LastName DESC and Name ASC
o.sortBy('LastName'.desc, 'Name'.asc).each(function(a, b) { console.log(a, b); });
/*
0 Object {Name: "Pirate", LastName: "Prentice"}
1 Object {Name: "Lazslo", LastName: "Jamf"}
2 Object {Name: "Pag", LastName: "Bodine"}
3 Object {Name: "Pig", LastName: "Bodine"}
*/
