Javascript test for existence of object key in a object with arrays

Question

I need to check if a property in a complex object (nested objects with arrays) exists or not. I found several posts on this subject, the most visited the one below. The problem with the provided solution (checkNested function) doesn't work with objects with arrays. Does anyone have a solution that cover this case as well?

Cheers.

javascript test for existence of nested object key

This the function I tested:

function checkProperty(obj, prop) {
 var parts = prop.split('.');
 for (var i = 0, l = parts.length; i < l; i++) {
 var part = parts[i];
 if (obj !== null && typeof obj === "object" && part in obj) {
 obj = obj[part];
 } else {
 return false;
 }
 }
 return true;
}

This is an example of my object:

{
 "_msgid": "3ae30deb.af9962",
 "topic": "",
 "payload": "I am really upset terrible service",
 "error": null,
 "parts": {
 "id": "3ae30deb.af9962",
 "type": "array",
 "count": 2,
 "len": 1,
 "index": 0
 },
 "case_id": "0001",
 "features": {
 "usage": {
 "text_units": 1,
 "text_characters": 34,
 "features": 7
 },
 "sentiment": {
 "document": {
 "score": -0.912124,
 "label": "negative"
 }
 },
 "semantic_roles": [{
 "subject": {
 "text": "I"
 },
 "sentence": "I am really upset terrible service",
 "object": {
 "text": "really upset terrible service",
 "keywords": [{
 "text": "terrible service"
 }]
 },
 "action": {
 "verb": {
 "text": "be",
 "tense": "present"
 },
 "text": "am",
 "normalized": "be"
 }
 }],
 "language": "en",
 "keywords": [{
 "text": "terrible service",
 "sentiment": {
 "score": -0.912124
 },
 "relevance": 0.902721,
 "emotion": {
 "sadness": 0.462285,
 "joy": 0.002207,
 "fear": 0.125395,
 "disgust": 0.17766,
 "anger": 0.575927
 }
 }],
 "entities": [],
 "emotion": {
 "document": {
 "emotion": {
 "sadness": 0.462285,
 "joy": 0.002207,
 "fear": 0.125395,
 "disgust": 0.17766,
 "anger": 0.575927
 }
 }
 },
 "concepts": [],
 "categories": [{
 "score": 0.99946,
 "label": "/health and fitness/disease/headaches and migraines"
 }, {
 "score": 0.0155692,
 "label": "/education/school"
 }, {
 "score": 0.0141217,
 "label": "/family and parenting/children"
 }]
 }
}

And a failure test:

console.log(checkProperty(msg, 'features.keywords[0].text') ? msg.features.keywords[0].text : "NA");

• anon: Can you provide an example that we can work with?
• Nina Scholz: you may add the array and the part what you have tried.
• Prerak Sola: Post a sample of your object and the code that you tried so far.
• gxvigo: I edited my question. Thanks

Answer 1

The checkProperty function you're using doesn't recognize brackets ([ and ]), it only understands dots. So, just give it dots:

checkProperty(msg, 'features.keywords.0.text');