如何通过搜索数组找出对象的数组位置？

Question

If I have an array like this:

var array1 = 
[
  {"phraseId":"abc",
  "keyword":"bb",
  "posId":1},
  {"phraseId":"def",
  "keyword":"bb",
  "posId":1},
]

How can I find out that the object with phraseId of "def" has the 2nd position?

Answer 1

您可以映射对象，仅返回目标字段，然后使用内置的indexOf获取位置：

array1.map(item => item.phraseId).indexOf('def')

Answer 2

Use native JavaScript findIndex method.

 var array1 = [{ "phraseId": "abc", "keyword": "bb", "posId": 1 }, { "phraseId": "def", "keyword": "bb", "posId": 1 }, ]; var pos = array1.findIndex(function(v) { // set your condition for finding object return v.phraseId == 'def'; // add `1` since you want to count from `1` }) + 1; console.log("Position of the object " + pos); 

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For older browser check polyfill option .

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With ES6 arrow function

 var array1 = [{ "phraseId": "abc", "keyword": "bb", "posId": 1 }, { "phraseId": "def", "keyword": "bb", "posId": 1 }, ]; var pos = array1.findIndex(v => v.phraseId == 'def') + 1; console.log("Position of the object " + pos); 

Answer 3

It works this way :

array1.forEach((elem, index) => {if (elem.phraseId === "def")
   console.log("index = " + index);
});

Answer 4

Assuming that your key is know (that you know you are looking for a phraseId always) then you can simply iterate through the array with a normal for loop if you are using "traditional" JS, or with a forEach if you are using ES6. Here's the simple for implementation.

for (var i = 0; i < array1.length; i++ ){
    if(array[i].phraseId === 'def') {
    // we know "i" is the index, so do something...
    }
}

To make it more generic so you can search any array for any key, make a function of it that returns the index:

function whatIndex (arr, key, val) {
    for (var i = 0; i < arr.length; i++) {
        if( arr[i][key] === val ) {
            return i;
        }
    }
}