Get Key value pairs from below object using javascript

Question

I am learning javascript and this may be a basic question, please help me to acheive below.

I am constructing an array inside obejct like below to use data later. Now, i have to send category as "Help" and need to get all it's subcategory values dynamically.

 [
    {"category":"Help","subcategory":"Email"},
    {"category":"Help","subcategory":"application"},
    {"category":"Help","subcategory":"Software"},
    {"category":"Help","subcategory":"Hardware"},
    {"category":"Request","subcategory":"Access"},
    {"category":"Request","subcategory":"Remote"},
    ]

Thanks in advance

Nina Scholz · Accepted Answer · 2017-04-19 10:34:05Z

You could filter with Array#filter first and then get the values with Array#map.

var array = [{ category: "Help", subcategory: "Email" }, { category: "Help", subcategory: "application" }, { category: "Help", subcategory: "Software" }, { category: "Help", subcategory: "Hardware" }, { category: "Request", subcategory: "Access" }, { category: "Request", subcategory: "Remote" }],
    subcategory = array
        .filter(a => a.category === 'Help')
        .map(a => a.subcategory);
    
console.log(subcategory);

.as-console-wrapper { max-height: 100% !important; top: 0; }

ES5

var array = [{ category: "Help", subcategory: "Email" }, { category: "Help", subcategory: "application" }, { category: "Help", subcategory: "Software" }, { category: "Help", subcategory: "Hardware" }, { category: "Request", subcategory: "Access" }, { category: "Request", subcategory: "Remote" }],
    subcategory = array
        .filter(function (a) { return a.category === 'Help'; })
        .map(function (a) { return a.subcategory; });
    
console.log(subcategory);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Mihai Alexandru-Ionut · Accepted Answer · 2017-04-19 10:32:32Z

2

You should use filter method in order to achieve this.

Also, use map method in order to create a new array only with the subcategories.

var array=[
    {"category":"Help","subcategory":"Email"},
    {"category":"Help","subcategory":"application"},
    {"category":"Help","subcategory":"Software"},
    {"category":"Help","subcategory":"Hardware"},
    {"category":"Request","subcategory":"Access"},
    {"category":"Request","subcategory":"Remote"},
];

var subcategories = array.filter(a => a.category === "Help").map(a => a.subcategory);
console.log(subcategories);

.as-console-wrapper { max-height: 100% !important; top: 0; }

edited Apr 19, 2017 at 10:32

answered Apr 19, 2017 at 10:21

Mihai Alexandru-Ionut

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1 Comment

a krishna Over a year ago

Hi Mihai, Thank you !! when i try to run the above script in browser console i am getting below error "Uncaught SyntaxError: Unexpected token =>". I will be really greatful if you can give me the steps to do it in detail

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