Lodash在下一个数组中查找对象

Question

I am currently working on an assignment in which I have to use Lodash and find an object inside JSON array. Below is my JSON string

var options = {
  'axisSeries': [
    ["xText", "xValue"],
    ["yText", "yValue"]
  ]
}

Now using Lodash I want to find string in 2nd Index of each array of axisSeries .

So for example if I search xValue . it should return me object as it is available in 2nd Index of First Array. Same for yValue .

But it should not return object for xText and yText as both of them are not available in second index.

to do so I want to use Lodash for that. But I could not find any appropriate function for this.

Answer 1

I think your JSON should be like,

var options = {
   'axisSeries': [
        { 'xText': 'X Text', 'xValue': 10 },
        { 'yText': 'Y Text', 'yValue': 20 }
    ]
}

And in Lodash use _.pluck() to get xValue like,

_.pluck(options.axisSeries, 'xValue');
// should return [10]

Alternatively, You can use _.map() ,

_.map(options.axisSeries, 'xValue');

If you want to get the whole array by xValue then you can use _.filter() like,

 var options = { 'axisSeries': [ ["xText", "xValue"], ["yText", "yValue"] ] } console.log( _.filter(options.axisSeries, function(o) { return o.indexOf('xValue')!=-1; }) ) 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script> 

Answer 2

You could use _.map with _.last , or if you need to get a specific index you could use _.nth . Also you should tell your teacher about ramda . it has a better structure and capability to compose functions.

 var options = { 'axisSeries': [ ["xText", "xValue"], ["yText", "yValue"] ] } console.log( _.map(options.axisSeries, _.last), _.map(options.axisSeries, xs => _.nth(xs, 1)) ) 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>