In the material select it's possible to add an array of entries with a number as a value. However when binding ngModel to a number property it throws an exception because the code behind checks explicitly for string values. https://mdbootstrap.com/angular/advanced/material-select/ get value(): string | string[] { return this.multiple ? this._value : this._value[0]; } set value(v: string | string[]) { if (typeof v === 'undefined' || v === null || v === '') { v = []; } else if (typeof v === 'string') { v = [v]; } else if (!Array.isArray(v)) { throw new TypeError('Value must be a string or an array.'); } if (!OptionList.equalValues(v, this._value)) { this.optionList.value = v; this.valueChanged(); } }

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