I have an array that looks like this: [[3, Apple], [4, Banana], [7, Orange], [9, Pear]]
Now I'd like to add all missing numbers from 1 to 10 with empty entries where I have the fruit in the example, so that as result I'd have:
[
[1, ],
[2, ],
[3, Apple],
[4, Banana],
[5, ],
[6, ],
[7, Orange],
[8, ],
[9, Pear]
[10, ]
]
I'd share what I've tried so far, but I really am stuck at the beginning. Has anybody an idea how to accomplish that?
let result = []
let fruits = [[3, 'Apple'], [4, 'Banana'], [7, 'Orange'], [9, 'Pear']]
let fruitsObject = Object.fromEntries(fruits)
for (let i = 1; i<=10; i++){
result.push(fruitsObject[i] ? [i, fruitsObject[i]] : [i])
}
console.log(result)
You can start by creating an array with indexes only, and then iterate over your data to fill in the missing values from your input.
const data = [[3, "Apple"], [4, "Banana"], [7, "Orange"], [9, "Pear"]]
const result = data.reduce((result, [id, val]) => {
result[id - 1].push(val);
return result;
}, Array.from({length: 10}, (_, i)=> [i + 1]))
console.log(result);Here 2nd argument of the reduce function is an array of length 10, filled with 1 element arrays, where element is an index + 1.
The first argument is a function called on every element of your input data, that modifies the 2nd argument.
A kind of over-engineering way. Don't be so hard on me.
const sourceArr = [[3, 'Apple'], [4, 'Banana'], [7, 'Orange'], [9, 'Pear']];
const sourceObj = Object.fromEntries(sourceArr);
const nullArr = [...Array(10).keys()].map(i => [i+1]);
const nullObj = Object.fromEntries(nullArr);
const unionObj = { ...nullObj, ...sourceObj };
const pairs = Object.entries(unionObj)
const result = pairs.map(pair => pair.filter(e => e));
console.log(result);.as-console-wrapper{min-height: 100%!important; top: 0}