Im trying to aggrigate huge array of objects to single object, but my if statements replace each other:
const obj = [];
res.map((el) => {
if (el.resource.name === "FORM01" && el.name === "cost.ttl") {
obj[el.resource.name] = { [el.name]: el };
}
if ( el.resource.name === "FORM01" && el.name === "cost.use") {
obj[el.resource.name] = { [el.name]: el };
}
});
in result I want to add in
obj[el.resource.name] = {}
two fields like cost.ttl and cost.use.
If you're not using the result, map isn't the right tool for looping through an array. Similarly, if you're mapping strings to values (el.resource.name to an object), an array isn't the correct object type to use. Just use a plain object, or a Map.
The reason your two assignments are conflicting is that the second time the condition is true, it overwrites the first object you've assigned. Instead, create an object, then add each property to the same object as necessary.
It's not clear what end result you're really looking for, but perhaps something like:
const obj = {}; // *** Object, not array
res.forEach((el) => { // *** forEach, not map
if (el.resource.name === "FORM01" && (el.name === "cost.ttl" || el.name === "cost.use")) {
// *** Get the existing object if any; create and store a new one if there isn't already one there
const entry = obj[el.resource.name] = obj[el.resource.name] || {};
// *** Add this property to it
entry[el.name] = el;
}
});
or you might use for-of:
const obj = {};
for (const el of res) {
if (el.resource.name === "FORM01" && (el.name === "cost.ttl" || el.name === "cost.use")) {
const entry = obj[el.resource.name] = obj[el.resource.name] || {};
entry[el.name] = el;
}
});
Try following
const obj = {}; // Initialize here to an object instead of array
res.map((el) => {
if (el.resource.name === "FORM01" && (el.name === "cost.ttl" || el.name === "cost.use")) {
// Check for existing object, else create new object
obj[el.resource.name] = obj[el.resource.name] || {};
obj[el.resource.name][el.name] = el; // set the value in object
}
});
Note, Array.map is not the correct choice over here for iteration as you are trying to loop over the array and get some value on an condition and store it. You can either use a simple for loop, or forEach.
map is the wrong tool if not using the array it creates. Edit: Oh, and what Jeremy said. :-)
obj should be an object. obj[el.resource.name] won't work on an Array, and your code didn't fix this.
Avoid two if statements in a row, because the first one could affect the data tested by the second one.
Also, obj should be an Object, not an Array.
Also also, use .forEach, not .map, because you're not returning anything from the loop.
const obj = {};
res.forEach( el => {
if (el.resource.name === "FORM01" && ["cost.ttl","cost.use"].includes(el.name)) {
obj["FORM01"] = { [el.name]: el };
}
});
obj["FORM01"]el.resource.name === "FORM01". Therefore obj[el.resource.name] === obj["FORM01"].el.resource.name === "FORM01" then, writing obj[el.resource.name] is exactly the same as writing obj["FORM01"]. So, I did it. This is what OP's code does.