How to find keys from undefined schema

Question

Suppose I have following array

array = [
 {
  optionA: "QA1",
  optionB: "QB1",
  optionC: "QC1",
  optionD: "QD1",
 },
 {
  optionA: "QA2",
  optionB: "QB2",
  optionC: "QC2",
  optionD: "QD2",
  optionE: "QD2",
 },
 {
  optionA: "QA3",
  optionB: "QB3",
 }
]

Expected output

tableHeader = {OptionA,OptionB,OptionC,OptionD,OptionE}

Wanted display questions data in a table format, which is not organised and has n number for options.

Tried all google searches and all JSON related websites, but not found on JSON keys grouping. — Milind P. Chaudhari, Sep 20 '22 at 11:32
The expected format is incorrect. I'm assuming you need all keys as an array — Rajesh, Sep 20 '22 at 11:37

score 2 · Accepted Answer · answered Sep 20 '22 at 11:35

2

You can get all keys as follows

const array = [{optionA: "QA1",optionB: "QB1",optionC: "QC1",optionD: "QD1",},{optionA: "QA2",optionB: "QB2",optionC: "QC2",optionD: "QD2",optionE: "QD2",},{optionA: "QA3",optionB: "QB3",}]

const allKeys = Object.keys(Object.assign({}, ...array))
console.log(allKeys)

answered Sep 20 '22 at 11:35

Rajesh

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1

Apparently SO is a "get code for free site" +1 – Yogi Sep 20 '22 at 11:44

score 1 · Answer 2 · edited Sep 20 '22 at 11:38

1

Try this one

let header = new Set();
array.forEach((a) => {
  Object.keys(a).forEach((item) => {
    header.add(item);
  });
});
console.log(header);

edited Sep 20 '22 at 11:38

hgb123

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answered Sep 20 '22 at 11:31

jobayer

156
1
5

How to find keys from undefined schema

2 Answers2