JavaScript findIndex returns the very first finded index in case of duplicate values
const arr = [{a: 10, b: 20, c: 30},{a: 15, b: 25, c: 32},{a: 10, b: 23, c: 350}]
const index = arr.findIndex(m => m.a === 10)
console.log(index);The above code will only return 0 index.
What should I do to get index 2 as well.
You could filter the keys of the array like this:
const arr = [{a: 10, b: 20, c: 30},{a: 15, b: 25, c: 32},{a: 10, b: 23, c: 350}]
const indices = [...arr.keys()].filter(i => arr[i].a === 10)
console.log(indices)Or, just use a for loop
const arr = [{a: 10, b: 20, c: 30},{a: 15, b: 25, c: 32},{a: 10, b: 23, c: 350}]
const output = [];
for (let i = 0; i < arr.length; i++) {
if (arr[i].a === 10)
output.push(i)
}
console.log(output)
arr.reduce((result, current, index) => {
return result.concat(current.a == 10 ? [index]: [])
})
You can use of Array.reduce to loop on your arr and returns every indexes
Single line :
const arr = [{
a: 10,
b: 20,
c: 30,
}, {
a: 15,
b: 25,
c: 32,
}, {
a: 10,
b: 23,
c: 350,
}]
// Value to check for
const v = 10;
// we loop on every entry of the arr
// we start with an empty array and look if the entries
// contains the value 10, if they do, we push the index of the
// entry in the array that was empty
//
// we do that for every entry of arr, when we treat all, we return
// the list of matching entries
const idx = arr.reduce((tmp, x, xi) => (x.a === v ? [...tmp, xi] : tmp), []);
console.log(idx);Explained :
const arr = [{
a: 10,
b: 20,
c: 30,
}, {
a: 15,
b: 25,
c: 32,
}, {
a: 10,
b: 23,
c: 350,
}]
const valToCheck = 10;
const indexes = arr.reduce((tmp, x, xi) => {
if (x.a === valToCheck) {
tmp.push(xi);
}
return tmp;
}, []);
console.log(indexes);Use map and filter:
const arr = [{a: 10, b: 20, c: 30},{a: 15, b: 25, c: 32},{a: 10, b: 23, c: 350}];
const res = arr.map(({ a }, i) => a == 10 ? i : "").filter(String);
console.log(res);You could map the indices of the found items and filter only valid indices.
const
array = [{ a: 10, b: 20, c: 30 }, { a: 15, b: 25, c: 32 }, { a: 10, b: 23, c: 350 }],
indices = array
.map((m, i) => m.a === 10 ? i : -1)
.filter(i => i != -1);
console.log(indices);You can just iterate through array and push matching index in new array.
const arr = [{a: 10, b: 20, c: 30},{a: 15, b: 25, c: 32},{a: 10, b: 23, c: 350}]
let p = []
arr.forEach((ele,index)=> ele.a===10 ? p.push(index) : '')
console.log(p)
You can try like this:
const arr = [{a: 10, b: 20, c: 30},{a: 15, b: 25, c: 32},{a: 10, b: 23, c: 350}];
const indices = arr.map((x, index) => {
if (x.a === 10) {
return index;
}
})
.filter(x => x !== undefined);
console.log(indices);If you want a function which works directly with Array, add this in Array.prototype
Array.prototype.findAllIndexes = function(iteratee){
var resultArray = [];
this.forEach(function(element) {
var validated = iteratee.call(this, element);
if(validated) {
resultArray.push(element);
}
});
return resultArray;
}Then you can use it anywher you want with array object
(please handle your corner cases based od data type you use)
const arr = [{a: 10, b: 20, c: 30},{a: 15, b: 25, c: 32},{a: 10, b: 23, c: 350}]
const index = arr.findAllIndexes(m => m.a === 10)
console.log(index);You can use some helper libraries to this kind of stuff like
lodash.js, you can include them in your project.
