updateOptions() — react Function Reference

Source Code

packages/react-dom-bindings/src/client/ReactDOMSelect.js lines 63–108

function updateOptions(
  node: HTMLSelectElement,
  multiple: boolean,
  propValue: any,
  setDefaultSelected: boolean,
) {
  const options: HTMLOptionsCollection = node.options;

  if (multiple) {
    const selectedValues = (propValue: Array<string>);
    const selectedValue: {[string]: boolean} = {};
    for (let i = 0; i < selectedValues.length; i++) {
      // Prefix to avoid chaos with special keys.
      selectedValue['$' + selectedValues[i]] = true;
    }
    for (let i = 0; i < options.length; i++) {
      const selected = selectedValue.hasOwnProperty('$' + options[i].value);
      if (options[i].selected !== selected) {
        options[i].selected = selected;
      }
      if (selected && setDefaultSelected) {
        options[i].defaultSelected = true;
      }
    }
  } else {
    // Do not set `select.value` as exact behavior isn't consistent across all
    // browsers for all cases.
    const selectedValue = toString(getToStringValue(propValue));
    let defaultSelected = null;
    for (let i = 0; i < options.length; i++) {
      if (options[i].value === selectedValue) {
        options[i].selected = true;
        if (setDefaultSelected) {
          options[i].defaultSelected = true;
        }
        return;
      }
      if (defaultSelected === null && !options[i].disabled) {
        defaultSelected = options[i];
      }
    }
    if (defaultSelected !== null) {
      defaultSelected.selected = true;
    }
  }
}