how to access nested json array

Question

I'm trying to access data in the following array but am having trouble using .forEach I want to access all singleLine.text but it won't let me. I am guessing because there are multiple singleLines at the same level.

var a = [ 
  { boxedCharacters: { text: '１０４００４３' } },
  { singleLine: { text: '東京都中央区日本橋新古町' } },
  { singleLine: { text: 'この度は、数多くのお店の中から当店を'} },
  { singleLine: { text: 'お選びご来店頂きまして誠にありがとう'} }
]

 a.forEach(function(value){
      console.log(value.singleLine.text)
      })

I've tried this but it isn't the best solution since it'll create an empty array for boxedCharacters because it won't match the passed in property value. Also, I could have multiple boxedCharaters and other keys with the same name.

function genNewArray(jsonArray)
 {return results.map(function(a){
 return {[jsonArray]: a[jsonArray]}
 })
}

var i = genArray(‘singleLine’)

Any better ideas of how I could access the values?

Possible duplicate of [Access / process (nested) objects, arrays or JSON](https://stackoverflow.com/questions/11922383/access-process-nested-objects-arrays-or-json) — Teemu, Apr 27 '18 at 16:25
Your first example is fine. You just have to account for the fact that not every object has a `singleLine` property. — Felix Kling, Apr 27 '18 at 16:27
Also, this isn't JSON, it's a JavaScript array. Nothing about your question is related to JSON. — Felix Kling, Apr 27 '18 at 16:28
@FelixKling ah, yes thanks. The actual data I am hanlding is a larger json but I just pulled the specific part I was having problem with. — Max, Apr 27 '18 at 16:31

score 0 · Answer 1 · answered Apr 27 '18 at 16:33

0

$.each(a, function(entryIndex, entry) {
  $.each(this.singleLine, function() { 
    alert(this.text); 
  }); 
 });

answered Apr 27 '18 at 16:33

parlad

1,143
4
23
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Give some explanation for your answer. Don't just post code, give a human context. – Okezie Apr 27 '18 at 18:08
There is absolutely no need to include a big library just to iterate over arrays. – CertainPerformance Apr 27 '18 at 18:19

score 0 · Answer 2 · answered Apr 27 '18 at 16:33

In first case it is failing because of this console.log(value.singleLine.text). Because the array also have a key named boxedCharacters and inside the forEach when the item is { boxedCharacters: { text: '１０４００４３' } }, it will not find value.singleLine. so it will fail

var a = [{
    boxedCharacters: {
      text: '１０４００４３'
    }
  },
  {
    singleLine: {
      text: '東京都中央区日本橋新古町'
    }
  },
  {
    singleLine: {
      text: 'この度は、数多くのお店の中から当店を'
    }
  }, {
    singleLine: {
      text: 'お選びご来店頂きまして誠にありがとう'
    }
  }
]

a.forEach(function(value) {
  if (value.singleLine) {
    console.log(value.singleLine.text)
  }

})

Actually, when I do this it works. So I don't think it's because of boxedCharacters being the problem but thanks for the answer. Really helped me better understand processing arrays a.forEach(function(value){ console.log(value.singleLine) }) — Max, Apr 30 '18 at 09:57

HMR · Accepted Answer · 2018-04-27T16:40:12.230

You could try the following:

    const a = [ 
      { boxedCharacters: { text: '１０４００４３' } },
      { singleLine: { text: '東京都中央区日本橋新古町' } },
      { singleLine: { text: 'この度は、数多くのお店の中から当店を'} },
      { singleLine: { text: 'お選びご来店頂きまして誠にありがとう'} }
    ];

    const getSingleLine = o => (o&&o.singleLine);
    const getText = o => (o&&o.text);
    const getSingleLineText = o => getText(getSingleLine(o))

    console.log(
      a.map(getSingleLineText)
      .filter(x=>!!x)//remove undefined
    )

Or you could reduce the object to the value and if the value doesn't exist return undefined:

const tryGet = keys => object =>
  keys.reduce(
    (o,key)=>
      (o!==undefined && o[key]!==undefined)
        ? o[key]
        : undefined,
    object
  );

const getSingleLineText = tryGet(["singleLine","text"]);

console.log(
  a.map(getSingleLineText)
  .filter(x=>!!x)//remove undefined
);

score 0 · Answer 4 · answered Apr 27 '18 at 16:34

0

You just need to test whether there is value for singleLine or not..

a.forEach(function(value){
  if(a.singleLine) console.log(value.singleLine.text)
})

answered Apr 27 '18 at 16:34

Incepter

2,711
15
33

how to access nested json array

4 Answers4