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Remove duplicates and map an array in JavaScript
Suppose, we have an array of objects like this −
const arr = [
{id:123, value:"value1", name:"Name1"},
{id:124, value:"value2", name:"Name1"},
{id:125, value:"value3", name:"Name2"},
{id:126, value:"value4", name:"Name2"}
];Note that some of the "name" property in objects within the array are duplicate.
We are required to write a JavaScript function that takes in one such array of objects. The function should then construct a new array of strings that contains only unique "name" property value from the array.
Therefore, the output for the above input should look like this −
const output = ["Name1", "Name2"];
Example
The code for this will be −
const arr = [
{id:123, value:"value1", name:"Name1"},
{id:124, value:"value2", name:"Name1"},
{id:125, value:"value3", name:"Name2"},
{id:126, value:"value4", name:"Name2"}
];
const pickNames = (arr = []) =>{
const res = [];
for (let i = arr.length; i−−;){
if (res.indexOf(arr[i].name) < 0) {
res.push(arr[i].name);
};
}
return res;
};
console.log(pickNames(arr));Output
And the output in the console will be −
[ 'Name2', 'Name1' ]
Updated on: 20-Nov-2020
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