select-with-options.html

<script>
    function createOption(parent, label, value) {
        var option = document.createElement('option');
        option.textContent = label;
        option.value = value;
        option.autoAdded = true;
        parent.appendChild(option);
    }

    new Polymer({
        is: 'select-with-options',
        extends: 'select',
        properties: {
            optionsList: { observer: '_renderOptions' },
            optionValue: { type: String },
            optionLabel: { type: String }
        },
        _renderOptions: function() {
            var currentValue = this.value;

            var baseOptions = [];
            while (this.firstChild) {
                if (!this.firstChild.autoAdded) {
                    baseOptions.push(this.firstChild);
                }
                this.removeChild(this.firstChild);
            }
            baseOptions.forEach(function(option) {
                this.appendChild(option);
            }, this);
            this.optionsList.forEach(function(option) {
                var label = this.optionLabel ? option[this.optionLabel] : option;
                var value = this.optionValue ? option[this.optionValue] : option;
                createOption(this, label, value);
            }, this);

            this.value = currentValue;
        }
    });
</script>