I would like to get back the result as a return value from the recursion, but I get 'undefined'. I read through all the related solutions (see ***) here, but somehow my example doesn't work. If I'm using a global variable then I can get the result otherwise the return values is 'undefined'.
https://stackblitz.com/edit/typescript-1b2ktw
export interface Needle {
needles: Needle[];
text: string;
}
export const Needles: Needle[] = [
{
text: 'root',
needles: [
{
text: 'a',
needles: [
{ text: 'a1', needles: null },
{ text: 'a2', needles: null },
],
},
{ text: 'b', needles: null },
],
},
];
let result;
function findNeedle(needles: Needle[], key: string, value: string): any {
needles.forEach((x) => {
if (x[key] === value) {
// return x as Needle; // doesnt work
result = x; // works just ugly
}
if (x.needles) {
needles = x.needles;
// return findNeedle(needles, key, value); solution *** like this doesnt work also
findNeedle(needles, key, value);
}
});
}
console.clear();
let x = findNeedle(Needles, 'text', 'a1');
console.log('x:', x, 'result', result);
--- CONSOLE
Console was cleared
x:undefined, result {text: "a1", needles: null}
How can I fix this to get back the result in return value ?
Thanks in advance.
Csaba
Don't use forEach, but a for..of loop. That way you can return something without being trapped within a callback function.
function findNeedle(needles: Needle[], key: string, value: string): any {
for (let x of needles) {
if (x[key] === value) return x;
if (x.needles) {
result = findNeedle(x.needles, key, value);
if (result) return result;
}
}
}
x is undefined because findNeedle() doesn't return a result, it assigns one instead to the result variable.