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JavaScript equivalents of some common C# LINQ methods. To help me remember!
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// JS array equivalents to C# LINQ methods - by Dan B. | |
// Here's a simple array of "person" objects | |
var people = [ | |
{ name: "John", age: 20 }, | |
{ name: "Mary", age: 35 }, | |
{ name: "Arthur", age: 78 }, | |
{ name: "Mike", age: 27 }, | |
{ name: "Judy", age: 42 }, | |
{ name: "Tim", age: 8 } | |
]; | |
// filter is equivalent to Where | |
var youngsters = people.filter(function (item) { | |
return item.age < 30; | |
}); | |
console.log("People younger than 30"); | |
console.log(youngsters); | |
// map is equivalent to Select | |
var names = people.map(function (item) { | |
return item.name; | |
}); | |
console.log("Just the names of people"); | |
console.log(names); | |
// every is equivalent to All | |
var allUnder40 = people.every(function (item) { | |
return item.age < 40; | |
}); | |
console.log("Are all people under 40?"); // false | |
console.log(allUnder40); | |
// some is equivalent to Any | |
var anyUnder30 = people.some(function (item) { | |
return item.age < 30; | |
}); | |
console.log("Are any people under 30?"); | |
console.log(anyUnder30); // true | |
// reduce is "kinda" equivalent to Aggregate (and also can be used to Sum) | |
var aggregate = people.reduce(function (item1, item2) { | |
return { name: '', age: item1.age + item2.age }; | |
}); | |
console.log("Aggregate age"); | |
console.log(aggregate.age); // { age: 210 } | |
// sort is "kinda" like OrderBy (but it sorts the array in place - eek!) | |
var orderedByName = people.sort(function (a, b) { | |
return a.name > b.name ? 1 : 0; | |
}) | |
console.log("Ordered by name"); | |
console.log(orderedByName); | |
// and, of course, you can chain function calls | |
var namesOfPeopleOver30OrderedDesc = people.filter(function (person) { | |
return person.age > 30; | |
}). | |
map(function (person) { | |
return person.name; | |
}). | |
sort(function (a, b) { | |
return a < b ? 1 : 0; | |
}); | |
console.log("And now.. the names of all people over 30 ordered by name descending"); | |
console.log(namesOfPeopleOver30OrderedDesc); |
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