I am trying to loop over a JavaScript object in ES6.
for (let [value, index] of object) {
do something with rest
if (index >= 1) {
// do something with first item
}
}
It works fine, although when I try to use index to get the first item it returns an error in console:
Uncaught TypeError: Invalid attempt to destructure non-iterable instance
Any ideas on how to loop over an object with index? thanks
This is just meant to be an addition to jonas w's solutions.
If you need the key of the current value:
const object = {a:2, b:4, c:6, d:8};
for (const [index, [key, value]] of Object.entries(Object.entries(object))) {
console.log(`${index}: ${key} = ${value}`);
}
Object.entries(object).forEach(([key, value], index) => {
console.log(`${index}: ${key} = ${value}`);
});Of course, you can leave out the key at any time:
const object = {a:2, b:4, c:6, d:8};
for (const [index, [, value]] of Object.entries(Object.entries(object))) {
console.log(`${index}: ${value}`);
}
Object.entries(object).forEach(([, value], index) => {
console.log(`${index}: ${value}`);
});
Simply count the index:
let index = 0;
for (let value of object) {
//do something with rest
if (index >= 1) {
// do something with the third and following items
}
index++;
}
Or if you really want to use object destructuring ( i dont know why ) its a bit more complicated:
let entries = Object.entries(object);
for(let [index, [key, value]] of entries.entries()){
//...
}
or:
for(let [index,value] of Object.values(object).entries()){
//...
}
But i dont know why youre not using a simple forEach?:
Object.values(obj).forEach((value, index)=> /*...*/);
index, key:
for (const [index, key] of Object.keys(object).entries()) {
// ...
}
index, value:
for (const [index, value] of Object.values(object).entries()) {
// ...
}
index, key, value:
for (const [index, [key, value]] of Object.entries(object).entries()) {
// ...
}
Just count the index:
let index = 0;
for (let value of object) {
if (index === 1) {
// do something with idx 1
}
// do something with the rest...
index++;
}Just use:
const obj = {
name: 'Bob',
age: 23,
city: 'Mexico',
};
for (const [key, value] of Object.entries(obj)) {
console.log(key, '=>', value)
}
Object.keys()to get an array of property names and then iterate that and there will be an index then, though again, it's probably not meaningful.for/ofloop will work as you want.object? Please post the whole code that throws this error (it suggest that yourobjectis iterable, but the elements are not).