js filter object of objects
// use filter() function. Let say we have array of object.
let arr = [
{name: "John", age: 30},
{name: "Grin", age: 10},
{name: "Marie", age: 50},
];
//Now I want an array in which person having age more than 40 is not
//there, i.e, I want to filter it out using age property. So
let newArr = arr.filter((person)=>(return person.age <= 40));
//filter function expects a function if it return true then it added
//into new array, otherwise it is ignored. So new Array would be
/* [
{name: "John", age: 30},
{name: "Grin", age: 10},
]
*/function objectFilter = (obj, predicate) =>
Object.keys(obj)
.filter( key => predicate(obj[key]) )
.reduce( (res, key) => (res[key] = obj[key], res), {} );
// Example use:
var scores = {
John: 2, Sarah: 3, Janet: 1
};
var filtered = objectFilter(scores, num => num > 1);
console.log(filtered);let newArray = array.filter(function(item) {
return condition;
});// Our data
const fruits = {
apple: {
qty: 300,
color: "green",
name: "apple",
price: 2
},
banana: {
qty: 130,
color: "yellow",
name: "banana",
price: 3
},
orange: {
qty: 120,
color: "orange",
name: "orange",
price: 1.5
},
melon: {
qty: 70,
color: "yellow",
name: "melon",
price: 5
}
};
// Now let"s create a map function
const map = (obj, fun) =>
Object.entries(obj).reduce(
(prev, [key, value]) => ({
...prev,
[key]: fun(key, value)
}),
{}
);
// Finally let's map by color for example
const myFruits = map(fruits, (_, fruit) => fruit.color);
/*
{ apple: 'green',
banana: 'yellow',
orange: 'orange',
melon: 'yellow' }
/*