gristlabs_grist-core/app/client/widgets/NumericEditor.ts

import {FieldOptions} from 'app/client/widgets/NewBaseEditor';
import {NTextEditor} from 'app/client/widgets/NTextEditor';

export class NumericEditor extends NTextEditor {
  constructor(protected options: FieldOptions) {
    if (!options.editValue && typeof options.cellValue === 'number') {
      // If opening a number for editing, we render it using the basic string representation (e.g.
      // no currency symbols or groupings), but it's important to use the right locale so that the
      // number can be parsed back (e.g. correct decimal separator).
      const locale = options.field.documentSettings.peek().locale;
      const fmt = new Intl.NumberFormat(locale, {useGrouping: false, maximumFractionDigits: 20});
      const editValue = fmt.format(options.cellValue);
      options = {...options, editValue};
    }
    super(options);
  }
}