简单的JavaScript转换JSON格式

Question

I have a json format and want to convert

Here are my script. I had tried but cannot get the correct results. Please give some advice, thanks and appreciate.

 function groupBy() { var list = [{ "id": "009", "Nm": "Model 1", "pid": "adidas" }, { "id": "007", "Nm": "Model 1", "pid": "adidas" }, { "id": "006", "Nm": "Model 1", "pid": "adidas" }, { "id": "pm1", "Nm": "Model 1", "pid": "puma" }, { "id": "003", "Nm": "Model 1", "pid": "adidas" }, { "id": "pm5", "Nm": "Model 1", "pid": "puma" }, { "id": "aj1", "Nm": "Model 1", "pid": "nike" }, { "id": "aj2", "Nm": "Model 1", "pid": "nike" } ]; var output = []; for (var i = 0; i < list.length; i++) { if (list[i].pid != undefined) { output.push(list[i]); } } console.log(output); } groupBy(); 

Answer 1

One option is to reduce into an object indexed by pid s, whose values are arrays. On each iteration, create the array at the appropriate property if it doesn't exist, and then push to that array:

 var list = [ {"id":"009","Nm":"Model 1","pid":"adidas"}, {"id":"007","Nm":"Model 1","pid":"adidas"}, {"id":"006","Nm":"Model 1","pid":"adidas"}, {"id":"pm1","Nm":"Model 1","pid":"puma"}, {"id":"003","Nm":"Model 1","pid":"adidas"}, {"id":"pm5","Nm":"Model 1","pid":"puma"}, {"id":"aj1","Nm":"Model 1","pid":"nike"}, {"id":"aj2","Nm":"Model 1","pid":"nike"} ]; console.log( list.reduce((a, item) => { const { pid } = item; if (!a[pid]) a[pid] = []; a[pid].push(item); return a; }, {}) ); 

Answer 2

You're pretty close there. But [] is to initialize an array instead of an object in javascript. In JS, it's {} .

Following is one of many ways you can accomplish this.

 function groupBy() { var list = [ {"id":"009","Nm":"Model 1","pid":"adidas"}, {"id":"007","Nm":"Model 1","pid":"adidas"}, {"id":"006","Nm":"Model 1","pid":"adidas"}, {"id":"pm1","Nm":"Model 1","pid":"puma"}, {"id":"003","Nm":"Model 1","pid":"adidas"}, {"id":"pm5","Nm":"Model 1","pid":"puma"}, {"id":"aj1","Nm":"Model 1","pid":"nike"}, {"id":"aj2","Nm":"Model 1","pid":"nike"} ]; // Initialize output as an object var output = {}; for (var i = 0; i < list.length; i++){ // 'objectKey' is where you group the list item by its 'pid' var objectKey = list[i].pid; // If there's a 'pid' in the list item, but 'output' is not an array yet, then.. if (objectKey && !output.hasOwnProperty(objectKey)){ // Initialize output.group to be an array output[ objectKey ] = []; } // Then finally, store the list into output's group that we created above. output[ objectKey ].push( list[i] ); } console.log(output); } groupBy(); 

Answer 3

Use this method for your any group by

const groupBy = function(arr, prop) {
  return arr.reduce(function(groups, item) {
    const val = item[prop]
    groups[val] = groups[val] || []
    groups[val].push(item)
    return groups
  }, {})
}

const list = [
                {"id":"009","Nm":"Model 1","pid":"adidas"},
                {"id":"007","Nm":"Model 1","pid":"adidas"},
                {"id":"006","Nm":"Model 1","pid":"adidas"},
                {"id":"pm1","Nm":"Model 1","pid":"puma"},
                {"id":"003","Nm":"Model 1","pid":"adidas"},
                {"id":"pm5","Nm":"Model 1","pid":"puma"},
                {"id":"aj1","Nm":"Model 1","pid":"nike"},
                {"id":"aj2","Nm":"Model 1","pid":"nike"}
            ];

const groupOutput = groupBy(list, 'pid');

You pass your key as second argument into groupBy for group by.