What is the best way to check if an object has items with negative values using javascript or ES6, if that is the case remove it from the object?
foo = { 0: 0, 1: -1, 2: 2, 3: -1}
result should be the one below
foo = { 0: 0, 1: 2}
Sorry, i am coming from a python background but i would love to hear from you.
You could filter the values and get a new object.
Assumptions:
m <= n, depending of the count of the positive values.The solution takes the values of the object in the standard order of ECMA-262 (Does JavaScript guarantee object property order?), filter this array and assigns the array to an object.
The result is an object with key and values from the filtered array.
const
data = { 0: 0, 1: -1, 2: 2, 3: -1 },
result = Object.assign({}, Object.values(data).filter(v => v >= 0));
console.log(result);
data = { 0: 0, 1: -1, 2: 2, 3: 4 }?
{ 0: 0, 1: 2, 2: 4 }{ 0: 0, 1: 2, 2: 2, 3:4 }You can use .filter to remove elements with negative values:
foo = { 0: 0, 1: -1, 2: 2, 3: -1}
let positives = Object.entries(foo).filter(e => e[1]>=0);
foo = {};
positives.forEach(([key, value], index) => {
foo[index] = value;
});
console.log(foo);If you want to modify the existing object rather than make a copy, you can do this:
let foo = { 0: 0, 1: -1, 2: 2, 3: -1}
for (let [key, value] of Object.entries(foo)) {
if (typeof value === "number" && value < 0) {
delete foo[key];
}
}
console.log(foo);Note: I added the typeof value === "number" as a type-safety check so you make sure you're comparing a numeric value in case there are other types of properties.
Or, in a reusable function that can be used with a user-supplied condition:
// callback passed (key, value) and
// return true to keep, false to remove the property
// function returns original object with desired properties removed
function filterProperties(obj, callback) {
for (let [key, value] of Object.entries(obj)) {
if (callback(key, value) === false) {
delete obj[key];
}
}
return obj;
}
let foo = { 0: 0, 1: -1, 2: 2, 3: -1}
filterProperties(foo, (key, value) => !(typeof value === "number" && value < 0));
console.log(foo);
If you want to create a new object
const fooWithoutNegativeValues = Object.entries(foo).reduce((acc, [key, value]) => value >= 0 ? {...acc, [key]: value} : acc)
To mutate its not different
const foo = { 0: 0, 1: -1, 2: 2, 3: -1}
const result = Object.keys(foo).reduce((acc, curr) => {
if(foo[curr] >= 0) {
acc[curr] = foo[curr]
}
return acc;
}, {})
console.log(result)-1 rather than check if it's negative.
foo, I updated the answer to check the negative values.This code will only modify the object to delete negatives.
foo = { 0: 0, 1: -1, 2: 2, 3: -1}
Object.keys(foo).map((key) => {
if(foo[key]<0){
delete foo[key]
}
})
console.log(foo);
For a short explanation, Object.keys(foo) will turn the object into an array based on the key names. Then .map() loops through each key in the array, and if the condition passes, it will delete the variable.
0). You should probably use an array.create a new onewould be fine