如何在 typescript 中使用每个（..）function？

Question

_.each(key_val, function(e){
            if($.inArray(e[0], names) == -1){
                var node = {};
                node.name = e[0];
                if(e[1]) {
                    node.value = e[1];
                    node.symbolSize = e[1] * nodeProp;
                }
                optionNodes.push(node);
                names.push(e[0]);
            }
        });

Above code from used angular.js I have to incorporate in angular typescript. here is "key_val" is array

Answer 1

forEach() method calls a function for each element in the array.

Syntax is as follows,

array.forEach(callback[, thisObject]);

where,

callback − Function to test for each element.

thisObject − Object to use as this when executing callback.

Example:

let num = [7, 8, 9];
num.forEach(function (value) {
  console.log(value);
}); 

On compiling, it will generate the following JavaScript code

var num = [7, 8, 9];
num.forEach(function (value) {
    console.log(value);
});

Its output is as follows

7
8
9

Answer 2

To achieve what your function is doing, you can create an array of object with name & value keys like this -

let key_val = [{name: 'c', value: 'xyz'}, {name: 'd', value: ''}];

Assuming you also have an array of names like -

let names = ['a', 'b'];

To iterate over each object in key_val array, you can use map like this -

key_val.map(item => {
  if(names.indexOf(item.name) === -1) {  //checking if item.name is present in names array or not
    var node = {};
    node.name = item.name;
    if(item.value) {
       node.value = item.name;
       node.symbolSize = item.name * nodeProp;
    }
    optionNodes.push(node);
    names.push(item.name);
  }
});