Trim Array value from specific char to specific char

Try like this:

export class AppComponent {

  Names = [
    "Name[name]",
    "Result[Type]",
    "Validation[Option]",
    "Status[Pointer]"
  ]


  constructor() {
    var modifiedNames = this.Names.map(x => x.split('[').pop().split(']')[0])
    console.log(modifiedNames)
  }
}

See Stackbiltz Demo

const array = [
 "Name[name]",
 "Result[Type]",
 "Validation[Option]",
 "Status[Pointer]"
];

const newArray = array.map(e => /^\w+\[(\w+)\]$/.exec(e)[1]);

// ["name", "Type", "Option", "Pointer"]

You can use substring method and based on the start and end bracket grab the subtring. To iterate on every element of array use map function, it creates a new array with the results of calling a provided function on every element in the calling array.

const arr =  [      
        "Name[name]",
        "Result[Type]",
        "Validation[Option]",
        "Status[Pointer]"
    ]

    let result = arr.map((a)=>{ return a.substring(a.indexOf("[") + 1 , a.indexOf("]")) });
    console.log(result);

You can loop through array and using following regex to get the desired output.

const array = [
  "Name[name]",
  "Result[Type]",
  "Validation[Option]",
  "Status[Pointer]"
];
var regexTest = new RegExp(/\[([^\]]+)\]/);
var newArray = array.map(e => regexTest.exec(e)[1]); 

fiddle link

substring and indexOf in action:

let newArray = [];
for(var i=0; i<array.length; i++){  
    var s = array[i];
    var n = s.indexOf('[');
    s = s.substring(n+1, s.length-1);
    newArray.push(s);
}

OR

let newArray = [];
for(var i=0; i<array.length; i++){  
    newArray.push(array[i].substring(array[i].indexOf('[')+1, array[i].length-1));
}