I am faced with the task of filtering a JavaScript map object based on an array of keys:
var arr = ['var1', 'var2', 'var3']
The Javascript map consists of four key-value pairs (var1: 1, var2: 2, var3: 3, var4: 4) and I need to extract only the items that match the keys in the arr array. Can someone assist me in achieving this filter operation?
To create a new object using the reduce method in JavaScript, you can follow this example:
const originalObject = {apple: 1, banana: 2, cherry: 3};
const keysToExtract = ["banana", "cherry", "date"];
const extractedObject = keysToExtract.reduce(function(result, key) {
if (originalObject.hasOwnProperty(key)) result[key] = originalObject[key];
return result;
}, {}); // {banana: 2, cherry: 3}
In order to remove a property from an object, you must utilize the delete operator.
var fruits = ['apple', 'banana', 'orange']
var animals = { lion:1, monkey:2, tiger:3, elephant:4};
var newAnimals = Object.assign({}, animals);
Object.keys(newAnimals).forEach(function(key){
if(!fruits.includes(key))
delete newAnimals[key];
});
console.log(newAnimals);If my memory serves me right, the situation at hand is as follows :
const keysToRetain = ["var1", "var2", "var3"];
const objectData = {
"var1": 1,
"var2": 2,
"var3": 3
};
If this assumption holds true, then you can implement the following approach :
const filteredResult = Object.entries(objectData)
.filter(item => keysToRetain.includes(item[0]))
.reduce((accumulator, entry)=>{
accumulator[entry[0]] = entry[1];
return accumulator;
}, {});
Alternatively,
const filteredResult = Object.entries(objectData)
.map(item => ({
"key": item[0],
"value": item[1]
})).filter(item => keysToRetain.includes(item.key))
.reduce((accumulator, entry)=>{
accumulator[entry.key] = entry.value;
return accumulator;
}, {});
This method essentially filters out entries in the object based on whether their key matches any of the specified keys, and then compacts them back into an object.
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