Angular filter to replace all underscores to spaces

In some case, you can use split() function.
.replace function is not compliant with regexp syntax (i.e. .replace(/,/g,'\n') syntax)

Full syntax:
{{myVar.toString().split(',').join('\n')}}

.toString() function is in case myVar is not typed as String in typescript.

string.replace not only accepts string as first argument but also it accepts regex as first argument. So put _ within regex delimiters / and aslo add g modifier along with that. g called global modifier which will do the replacement globally.

App.filter('underscoreless', function () {
  return function (input) {
      return input.replace(/_/g, ' ');
  };
});

This simple function can do it:

public getCleanedString(cadena) {
    cadena = cadena.replace(/_/g, ' ');
    return cadena;
  }

Here's a generic replace filter alternative

App.filter('strReplace', function () {
  return function (input, from, to) {
    input = input || '';
    from = from || '';
    to = to || '';
    return input.replace(new RegExp(from, 'g'), to);
  };
});

Use it as follows in your HTML:

{{ addText | strReplace:'_':' ' }}

Minor note: Any HTML tags in the to parameter will cause the expression to fail due to Angular content security rules.