How to check if a value exists in an object using JavaScript

Question

I have an object in JavaScript  var obj         quot a quot    quot test1 quot       quot b quot    quot test2 quot     How do I check that test1 exists in the object as a value

User · Answer

For a one-liner  I would say  exist   Object values obj  includes  quot test1 quot    console log exist

User · Answer

Shortest ES6  one liner   let exists   Object values obj  includes  test1

User · Answer

getValue   function  object  key        return key split  quot   quot   reduce function  obj  val            return  typeof obj     quot undefined quot     obj     null    obj      quot  quot     obj      isString obj val     obj val  trim     obj val      object       var obj         quot a quot    quot test1 quot       quot b quot    quot test2 quot      Function called   getValue obj   quot a quot

User · Answer

var obj     quot a quot    quot test1 quot    quot b quot    quot test2 quot    var getValuesOfObject   Object values obj  for index   0  index  lt  getValuesOfObject length  index         return Boolean getValuesOfObject index       quot test1 quot      The Object values   method returned an array  assigned to getValuesOfObject  containing the given object s  obj  own enumerable property values  The array was iterated using the for loop to retrieve each value  values in the getValuesfromObject  and returns a Boolean   function to find out if the expression   quot text1 quot  is a value in the looping array  is true

User · Answer

You can use Object values        The Object values   method returns an array of a given object s own   enumerable property values  in the same order as that provided by a   for   in loop  the difference being that a for-in loop enumerates   properties in the prototype chain as well     and then use the indexOf   method      The indexOf   method returns the first index at which a given   element can be found in the array  or -1 if it is not present    For example   Object values obj  indexOf  test     gt   0   A more verbose example is below      x000D   x000D  var obj     x000D     a    test1   x000D     b    test2  x000D    x000D   x000D   x000D  console log Object values obj  indexOf  test1        0 x000D  console log Object values obj  indexOf  test2        1 x000D   x000D  console log Object values obj  indexOf  test1    gt   0      true x000D  console log Object values obj  indexOf  test2    gt   0      true  x000D   x000D  console log Object values obj  indexOf  test10        -1 x000D  console log Object values obj  indexOf  test10    gt   0      false x000D   x000D   x000D

User · Answer

if  myObj hasOwnProperty  key    amp  amp  myObj  key       value

User · Answer

This should be a simple check  Example 1 var myObj     quot a quot    quot test1 quot    if myObj a     quot test1 quot         alert  quot test1 exists  quot

User · Answer

Use a for   in loop  for  let k in obj        if  obj k       quot test1 quot             return true

User · Answer

You can use the Array method  some   var exists   Object keys obj  some function k        return obj k       test1

User · Answer

You can try this   function checkIfExistingValue obj  key  value        return obj hasOwnProperty key   amp  amp  obj key      value    var test     name    jack   sex  F    name   joe   sex  M   console log test some function person    return checkIfExistingValue person   name    jack

User · Answer

The simple answer to this is given below  This is working because every JavaScript type has a    constructor    property on it prototype     let array      array constructor     Array      gt  true   let data      data constructor     Object      gt  true

User · Answer

Try   x000D   x000D  var obj         a    test1       b    test2      Object keys obj  forEach function key      if  obj key      test1         alert  exists            x000D   x000D   x000D   Or  x000D   x000D  var obj         a    test1       b    test2      var found   Object keys obj  filter function key      return obj key       test1        if  found length       alert  exists      x000D   x000D   x000D   This will not work for NaN and -0 for those values  You can use  instead of      what is new in ECMAScript  6   Object is obj key   value    With modern browsers you can also use   x000D   x000D  var obj         a    test1       b    test2      if  Object values obj  includes  test1        alert  exists      x000D   x000D   x000D

User · Answer

You can turn the values of an Object into an array and test that a string is present   It assumes that the Object is not nested and the string is an exact match   var obj     a   test1   b   test2     if  Object values obj  indexOf  test1    gt  -1       console log  has test1        https   developer mozilla org en-US docs Web JavaScript Reference Global Objects Object values

User · Answer

you can try this one var obj        quot a quot    quot test1 quot      quot b quot    quot test2 quot      const findSpecificStr    obj  str    gt      return Object values obj  includes str      findSpecificStr obj   test1

User · Answer

I did a test with all these examples  and I ran this in Node js v8 11 2  Take this as a guide to select your best choice   x000D   x000D  let i  tt      const obj     a   test1   b   test2   c   test3   d   test4   e   test5   f   test6      console time  test1   i   0  for    i lt 1000000  i i 1      if  Object values obj  indexOf  test4    gt  -1        tt   true        console timeEnd  test1    console time  test1 1   i   0  for    i lt 1000000   i i 1      if   Object values obj  indexOf  test4          tt   true        console timeEnd  test1 1    console time  test2   i   0  for    i lt 1000000  i i 1      if  Object values obj  includes  test4          tt   true        console timeEnd  test2     console time  test3   i   0  for    i lt 1000000   i i 1      for const item in obj        if obj item      test4           tt   true        break              console timeEnd  test3    console time  test3 1   i   0  for    i lt 1000000  i i 1      for const  item  value  in obj        if value     test4           tt   true        break              console timeEnd  test3 1     console time  test4   i   0  for    i lt 1000000  i i 1      tt   Object values obj  some  val  val2    gt        return val     test4          console timeEnd  test4    console time  test5   i   0  for    i lt 1000000  i i 1      const arr   Object keys obj     const len   arr length    let i2   0    for    i2 lt len   i2 i2 1        if obj arr i2       test4           tt   true        break              console timeEnd  test5   x000D   x000D   x000D   Output on my server test1    272 325 ms test1 1  246 316 ms test2    251 98 0ms test3     73 284 ms test3 1  102 029 ms test4    339 299 ms test5     85 527 ms

[javascript] How to check if a value exists in an object using JavaScript

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