Method synchronizeValue

src/select-value-observer.js:74–127

()

  }

  synchronizeValue() {
    let options = this.element.options;
    let count = 0;
    let value = [];

    for (let i = 0, ii = options.length; i < ii; i++) {
      let option = options.item(i);
      if (!option.selected) {
        continue;
      }
      value.push(option.hasOwnProperty('model') ? option.model : option.value);
      count++;
    }

    if (this.element.multiple) {
      // multi-select
      if (Array.isArray(this.value)) {
        let matcher = this.element.matcher || ((a, b) => a === b);
        // remove items that are no longer selected.
        let i = 0;
        while (i < this.value.length) {
          let a = this.value[i];
          if (value.findIndex(b => matcher(a, b)) === -1) { // eslint-disable-line no-loop-func
            this.value.splice(i, 1);
          } else {
            i++;
          }
        }
        // add items that have been selected.
        i = 0;
        while (i < value.length) {
          let a = value[i];
          if (this.value.findIndex(b => matcher(a, b)) === -1) { // eslint-disable-line no-loop-func
            this.value.push(a);
          }
          i++;
        }
        return; // don't notify.
      }
    } else {
      // single-select
      if (count === 0) {
        value = null;
      } else {
        value = value[0];
      }
    }

    if (value !== this.value) {
      this.oldValue = this.value;
      this.value = value;
      this.notify();
    }
  }

  notify() {
    let oldValue = this.oldValue;