按值在深层嵌套 object 中查找 object

Question

I would like to find an object id in deep nested object by value. I try to do it with recursion, but can't figure out why got 'undefined'.

In this code I have in console "final result: 234324234" which is correct, but for some reason this result is not returning from this function.

Please, take a look.

demo in jsbin

 let obj = { "uuid": "344444", "entityName": "priceFormationPhase", "id": 2, "value": "foo", "children": { "4": { "uuid": "44444", "entityName": "organization", "id": 4, "value": "ffffff", "children": { "344534": { "uuid": "33333", "entityName": "contract", "id": 928688, "value": "dh", "children": { "345345": { "uuid": "222222222", "entityName": "contractPhase", "id": 234324234, "value": "111", "children": {} } } } } } } }; function findContractStage(obj) { if ((typeof obj.children === 'object') && (Object.keys(obj.children).length > 0)) { findContractStage(obj.children); } else if (typeof obj[Object.keys(obj)[0]] === 'object') { findContractStage(obj[Object.keys(obj)[0]]); } else if (obj.entityName) { console.log(`final result: ${obj.id}`); return obj.id; } } let contractStageId = findContractStage(obj); console.log(`contractStageId: ${contractStageId}`);

Answer 1

You're not returning the value you get when you recurse. Try this:

 let obj = { "uuid": "344444", "entityName": "priceFormationPhase", "id": 2, "value": "foo", "children": { "4": { "uuid": "44444", "entityName": "organization", "id": 4, "value": "ffffff", "children": { "344534": { "uuid": "33333", "entityName": "contract", "id": 928688, "value": "dh", "children": { "345345": { "uuid": "222222222", "entityName": "contractPhase", "id": 234324234, "value": "111", "children": {} } } } } } } }; function findContractStage(obj) { if ((typeof obj.children === 'object') && (Object.keys(obj.children).length > 0)) { return findContractStage(obj.children); } else if (typeof obj[Object.keys(obj)[0]] === 'object') { return findContractStage(obj[Object.keys(obj)[0]]); } else if (obj.entityName) { console.log(`final result: ${obj.id}`); return obj.id; } } let contractStageId = findContractStage(obj); console.log(`contractStageId: ${contractStageId}`);

Answer 2

You forget to return the function

 let obj = { "uuid": "344444", "entityName": "priceFormationPhase", "id": 2, "value": "foo", "children": { "4": { "uuid": "44444", "entityName": "organization", "id": 4, "value": "ffffff", "children": { "344534": { "uuid": "33333", "entityName": "contract", "id": 928688, "value": "dh", "children": { "345345": { "uuid": "222222222", "entityName": "contractPhase", "id": 234324234, "value": "111", "children": {} } } } } } } }; function findContractStage(obj) { if ((typeof obj.children === 'object') && (Object.keys(obj.children).length > 0)) { return findContractStage(obj.children); } else if (typeof obj[Object.keys(obj)[0]] === 'object') { return findContractStage(obj[Object.keys(obj)[0]]); } else if (obj.entityName) { console.log(`final result: ${obj.id}`); return obj.id; } } let contractStageId = findContractStage(obj); console.log(`contractStageId: ${contractStageId}`);

Answer 3

You need to add "return" before recursive calls

return findContractStage(obj.children);

and

return findContractStage(obj[Object.keys(obj)[0]]);

So your recursive function goes deeper as it can and return your id value.