Find by key deep in a nested array

Question

Let s say I have an object                    title    some title           channel id   123we           options                                            channel id   abc                   image   http   asdasd com all-inclusive-block-img jpg                   title   All-Inclusive                   options                                                   channel id   dsa2                           title   Some Recommends                           options                                                                   image   http   www asdasd com                                   title   Sandals                                   id   1                                   content                                               I want to find the one object where the id is 1  Is there a function for something like this  I could use Underscore s   filter method  but I would have to start at the top and filter down

User · Answer

Improved answer to take into account circular references within objects. It also displays the path it took to get there.

In this example, I am searching for an iframe that I know is somewhere within a global object:

const objDone = []
var i = 2
function getObject(theObject, k) {
    if (i < 1 || objDone.indexOf(theObject) > -1) return
    objDone.push(theObject)
    var result = null;
    if(theObject instanceof Array) {
        for(var i = 0; i < theObject.length; i++) {
            result = getObject(theObject[i], i);
            if (result) {
                break;
            }   
        }
    }
    else
    {
        for(var prop in theObject) {
            if(prop == 'iframe' && theObject[prop]) {
                i--;
                console.log('iframe', theObject[prop])
                return theObject[prop]
            }
            if(theObject[prop] instanceof Object || theObject[prop] instanceof Array) {
                result = getObject(theObject[prop], prop);
                if (result) {
                    break;
                }
            } 
        }
    }
    if (result) console.info(k)
    return result;
}

Running the following: getObject(reader, 'reader') gave the following output and the iframe element in the end:

iframe // (The Dom Element)
_views
views
manager
rendition
book
reader

NOTE: The path is in reverse order reader.book.rendition.manager.views._views.iframe

User · Answer

Improved  haitaka answer  using the key and predicate function  deepSearch  object  key  predicate        if  object hasOwnProperty key   amp  amp  predicate key  object key       true  return object      for  let i   0  i  lt  Object keys object  length  i            let value   object Object keys object  i          if  typeof value      quot object quot   amp  amp  value    null            let o   deepSearch object Object keys object  i    key  predicate          if  o    null  return o                   return null    So this can be invoked as  var result   deepSearch myObject   id    k  v    gt  v     1    or var result   deepSearch myObject   title    k  v    gt  v      Some Recommends     Here is the demo  http   jsfiddle net a21dx6c0  EDITED In the same way you can find more than one object function deepSearchItems object  key  predicate            let ret               if  object hasOwnProperty key   amp  amp  predicate key  object key       true                ret       ret  object                     if  Object keys object  length                for  let i   0  i  lt  Object keys object  length  i                      let value   object Object keys object  i                    if  typeof value      quot object quot   amp  amp  value    null                        let o   this deepSearchItems object Object keys object  i    key  predicate                       if  o    null  amp  amp  o instanceof Array                            ret       ret     o                                                                           return ret

User · Answer

Another  somewhat silly  option is to exploit the naturally recursive nature of JSON stringify  and pass it a replacer function which runs on each nested object during the stringification process   x000D   x000D  const input         title    some title      channel id    123we      options           channel id    abc        image    http   asdasd com all-inclusive-block-img jpg        title    All-Inclusive        options             channel id    dsa2          title    Some Recommends          options               image    http   www asdasd com            title    Sandals            id    1            content                                console log findNestedObj input   id    1      function findNestedObj entireObj  keyToFind  valToFind      let foundObj    JSON stringify entireObj      nestedValue    gt        if  nestedValue  amp  amp  nestedValue keyToFind      valToFind          foundObj   nestedValue            return nestedValue          return foundObj     x000D   x000D   x000D

User · Answer

Iulian Pinzaru s answer was almost exactly what I needed  but it doesn t work if your objects have any null values  This version fixes that   function  deepSearch  object  key  predicate      if  object hasOwnProperty key   amp  amp  predicate key  object key       true  return object    for  let i   0  i  lt  Object keys object  length  i          const nextObject   object Object keys object  i        if  nextObject  amp  amp  typeof nextObject      object           let o   deepSearch nextObject  key  predicate        if  o    null  return o             return null

User · Answer

Some time ago I have made a small lib find-and  which is available on npm  for working with nested objects in a lodash manner  There s the returnFound function which returns the found object  or an object array if there s more than one object found   E g    const findAnd   require  find-and     const a              title    some title        channel id   123we        options                      channel id   abc            image   http   asdasd com all-inclusive-block-img jpg            title   All-Inclusive            options                             channel id   dsa2                title   Some Recommends                options                                     image   http   www asdasd com                    title   Sandals                    id   1                    content                                                                                       findAnd returnFound a   id   1       returns       image   http   www asdasd com      title   Sandals      id   1      content

User · Answer

Just use recursive function  See example below   x000D   x000D  const data             title   some title       channel id   123we       options                    channel id   abc           image   http   asdasd com all-inclusive-block-img jpg           title   All-Inclusive           options                            channel id   dsa2               title   Some Recommends               options                                    image   http   www asdasd com                   title   Sandals                   id   1                   content                                                                               function  find collection  key  value      for  const o of collection        for  const  k  v  of Object entries o           if  k     key  amp  amp  v     value            return o               if  Array isArray v             const  o    find v  key  value          if   o              return  o                                console log  find data   channel id    dsa2    x000D   x000D   x000D

User · Answer

I found this page through googling for the similar functionalities  Based on the work provided by Zach and regularmike  I created another version which suits my needs  BTW  teriffic work Zah and regularmike  I ll post the code here   function findObjects obj  targetProp  targetValue  finalResults       function getObject theObject        let result   null      if  theObject instanceof Array          for  let i   0  i  lt  theObject length  i              getObject theObject i                      else         for  let prop in theObject            if theObject hasOwnProperty prop              console log prop          theObject prop              if  prop     targetProp                console log  --found id                if  theObject prop      targetValue                  console log  ----found porop   prop        theObject prop                  finalResults push theObject                                       if  theObject prop  instanceof Object    theObject prop  instanceof Array               getObject theObject prop                                               getObject obj        What it does is it find any object inside of obj with property name and value matching to targetProp and targetValue and will push it to the finalResults array  And Here s the jsfiddle to play around  https   jsfiddle net alexQch 5u6q2ybc

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If you want to get the first element whose id is 1 while object is being searched  you can use this function   function customFilter object       if object hasOwnProperty  id    amp  amp  object  id      1          return object       for var i 0  i lt Object keys object  length  i             if typeof object Object keys object  i       object                var o   customFilter object Object keys object  i                 if o    null                  return o                       return null      If you want to get all elements whose id is 1  then  all elements whose id is 1 are stored in result as you see    function customFilter object  result       if object hasOwnProperty  id    amp  amp  object id    1          result push object        for var i 0  i lt Object keys object  length  i             if typeof object Object keys object  i       object                customFilter object Object keys object  i    result

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x000D   x000D      fucntion getPath obj  path  index   0            const nestedKeys   path split              const selectedKey   nestedKeys index           if  index     nestedKeys length - 1                return obj selectedKey                     if   obj hasOwnProperty selectedKey                 return                       const nextObj   obj selectedKey           return Utils hasPath nextObj  path  index   1        x000D   x000D   x000D   You re welcome By  Gorillaz

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I d like to suggest an amendment to Zach RegularMike s answer  but don t have the  reputation  to be able to comment    I found there solution a very useful basis  but suffered in my application because if there are strings within arrays it would recursively call the function for every character in the string  which caused IE11  amp  Edge browsers to fail with  out of stack space  errors   My simple optimization was to add the same test used in the  object  clause recursive call to the one in the  array  clause   if  arrayElem instanceof Object    arrayElem instanceof Array      Thus my full code  which is now looking for all instances of a particular key  so slightly different to the original requirement  is      Get all instances of specified property deep within supplied object function getPropsInObject theObject  targetProp        var result           if  theObject instanceof Array            for  var i   0  i  lt  theObject length  i                  var arrayElem   theObject i               if  arrayElem instanceof Object    arrayElem instanceof Array                    result   result concat getPropsInObject arrayElem  targetProp                                  else           for  var prop in theObject                var objProp   theObject prop               if  prop    targetProp                    return theObject prop                             if  objProp instanceof Object    objProp instanceof Array                    result   result concat getPropsInObject objProp  targetProp                                      return result

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We use object-scan for our data processing  It s conceptually very simple  but allows for a lot of cool stuff  Here is how you would solve your specific question  x000D   x000D     const objectScan   require  object-scan     const find    id  input    gt  objectScan             abort  true    rtn   value     filterFn     value      gt  value id     id    input    const data      title   some title   channel id   123we   options     channel id   abc   image   http   asdasd com all-inclusive-block-img jpg   title   All-Inclusive   options     channel id   dsa2   title   Some Recommends   options     image   http   www asdasd com   title   Sandals   id   1   content                   console log find  1   data         gt    image   http   www asdasd com   title   Sandals   id   1   content       x000D   as-console-wrapper  max-height  100   important  top  0  x000D   lt script src  https   bundle run object-scan 13 8 0  gt  lt  script gt  x000D   x000D   x000D   Disclaimer  I m the author of object-scan

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This piece of code allows you to get all objects within a JSON whose key is user-defined   function main obj       property    const views         function traverse o        for  var i in o          if i     property  views push o i          if    o i   amp  amp  typeof o i     object             console log i  o i            traverse o i            else           console log i  o i                           traverse obj     return views          Here is an example   const obj         id   id at level 1       level2          id   id at level 2         level3            id   id at level 3           level4              level5                id   id at level 5                                    text        main obj   id

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What worked for me was this lazy approach  not algorithmically lazy      if  JSON stringify object name  indexOf  key name    gt  -1         console log  Key Found      else      console log  Key not Found

User · Answer

If you re already using Underscore  use   find      find yourList  function  item        return item id     1

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I ve created library for this purpose  https   github com dominik791 obj-traverse  You can use findFirst   method like this   var foundObject   findFirst rootObject   options      id    1        And now foundObject variable stores a reference to the object that you re looking for

User · Answer

Another recursive solution  that works for arrays lists and objects  or a mixture of both  function deepSearchByKey object  originalKey  matches              if object    null            if Array isArray object                 for let arrayItem of object                    deepSearchByKey arrayItem  originalKey  matches                           else if typeof object     object                  for let key of Object keys object                     if key    originalKey                        matches push object                     else                       deepSearchByKey object key   originalKey  matches                                                           return matches     usage  let result   deepSearchByKey arrayOrObject   key       returns an array with the objects containing the key

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Recursion is your friend  I updated the function to account for property arrays   function getObject theObject        var result   null      if theObject instanceof Array            for var i   0  i  lt  theObject length  i                  result   getObject theObject i                if  result                    break                                       else               for var prop in theObject                console log prop          theObject prop                if prop     id                     if theObject prop     1                        return theObject                                              if theObject prop  instanceof Object    theObject prop  instanceof Array                    result   getObject theObject prop                    if  result                        break                                                       return result      updated jsFiddle  http   jsfiddle net FM3qu 7

[javascript] Find by key deep in a nested array

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