I’m trying to better understand how to work with nested JSON objects in JavaScript/React.
I am getting data through the GitLab API in the following form:
const merge_requests = [
{
"id": 39329289,
"iid": 156,
"project_id": 231,
"title": "Repaired some Links",
"description": "",
"state": "merged",
"created_at": "2022-12-03T12:22:14.690Z",
"updated_at": "2022-12-03T12:22:20.060Z",
"merged_by": {
"id": 1000,
"username": "test.user",
"name": "[email protected]",
"state": "active",
"avatar_url": "",
"web_url": ""
},
"merge_user": {
"id": 2802,
"username": "tes.user",
"name": "[email protected]",
"state": "active",
"avatar_url": "",
"web_url": ""
},
"merged_at": "2022-12-03T12:22:20.072Z",
"closed_by": null,
"closed_at": null,
"assignees": [],
"assignee": null,
"reviewers": [],
"source_project_id": 231,
"target_project_id": 231,
"labels": [],
"squash_commit_sha": null,
"discussion_locked": null,
"should_remove_source_branch": null,
"force_remove_source_branch": null,
"reference": "!156",
"references": {
"short": "!156",
"relative": "!156",
"full": ""
},
"web_url": "",
"time_stats": {
"time_estimate": 0,
"total_time_spent": 0,
"human_time_estimate": null,
"human_total_time_spent": null
},
"squash": false,
"task_completion_status": {
"count": 0,
"completed_count": 0
},
"has_conflicts": false,
"blocking_discussions_resolved": true,
"approvals_before_merge": null
},
{
"id": 39329289,
"iid": 156,
"project_id": 231,
"title": "Repaired some Links",
"description": "",
"state": "merged",
"created_at": "2022-12-03T12:22:14.690Z",
"updated_at": "2022-12-03T12:22:20.060Z",
"merged_by": {
"id": 1000,
"username": "test.user",
"name": "[email protected]",
"state": "active",
"avatar_url": "",
"web_url": ""
},
"merge_user": {
"id": 2802,
"username": "test.user",
"name": "[email protected]",
"state": "active",
"avatar_url": "",
"web_url": ""
},
"merged_at": "2022-12-03T12:22:20.072Z",
"closed_by": null,
"closed_at": null,
"assignees": [],
"assignee": null,
"reviewers": [],
"source_project_id": 231,
"target_project_id": 231,
"labels": [],
"squash_commit_sha": null,
"discussion_locked": null,
"should_remove_source_branch": null,
"force_remove_source_branch": null,
"reference": "!156",
"references": {
"short": "!156",
"relative": "!156",
"full": ""
},
"web_url": "",
"time_stats": {
"time_estimate": 0,
"total_time_spent": 0,
"human_time_estimate": null,
"human_total_time_spent": null
},
"squash": false,
"task_completion_status": {
"count": 0,
"completed_count": 0
},
"has_conflicts": false,
"blocking_discussions_resolved": true,
"approvals_before_merge": null
},]
I want to loop through all objects(merge requests) in this JSON and create a new array with the merge_user.name.
console.log(merge_requests[0].merge_user.name);
console.log(merge_requests[1].merge_user.name);
The logs above return both the correct values. However, I cannot loop through the JSON to create a new array from the data like this:
const arrTest = [];
for(var i = 0; i < Object.keys(merge_requests).length; i++)
{
var mergeUserName = merge_requests[i].merge_user.name;
arrTest.push(mergeUserName);
}
console.log(arrTest);
}
The code above leads to the following error: Uncaught (in promise) TypeError: resultData[i].merge_user is null
Here is a picture:
I am currently learning JS coming from R. I have huge problems working with JSON instead of dataframes and I cannot find any documentation to learn from. I would appreciated any advice/ sources.
4
Answers
There is no need to use
Object.keys(),you can usemerge_requests.lengthdirectlymerge_requests[i].merge_user?.namewill returnundefinedif object is not present in the json.I copy & pasted your code & JSON and it works fine.
Make sure your JSON is parsed after getting it from ate API
typeof merge_requestsshould returnobject, if it returnsstringthen do the following:const parsedData = JSON.parse(merge_requests)and loop throughparsedDatai checked your code it’s working fine.
Check your api request, are you sure you waiting for it till it get fulfilled?