Function update

static/bootstrap4/js/bootstrap.bundle.js:2417–2461

* Updates the position of the popper, computing the new offsets and applying * the new style. * Prefer `scheduleUpdate` over `update` because of performance reasons. * @method * @memberof Popper

()

   * @memberof Popper
   */
  function update() {
    // if popper is destroyed, don't perform any further update
    if (this.state.isDestroyed) {
      return;
    }

    var data = {
      instance: this,
      styles: {},
      arrowStyles: {},
      attributes: {},
      flipped: false,
      offsets: {}
    };

    // compute reference element offsets
    data.offsets.reference = getReferenceOffsets(this.state, this.popper, this.reference, this.options.positionFixed);

    // compute auto placement, store placement inside the data object,
    // modifiers will be able to edit `placement` if needed
    // and refer to originalPlacement to know the original value
    data.placement = computeAutoPlacement(this.options.placement, data.offsets.reference, this.popper, this.reference, this.options.modifiers.flip.boundariesElement, this.options.modifiers.flip.padding);

    // store the computed placement inside `originalPlacement`
    data.originalPlacement = data.placement;

    data.positionFixed = this.options.positionFixed;

    // compute the popper offsets
    data.offsets.popper = getPopperOffsets(this.popper, data.offsets.reference, data.placement);

    data.offsets.popper.position = this.options.positionFixed ? 'fixed' : 'absolute';

    // run the modifiers
    data = runModifiers(this.modifiers, data);

    // the first `update` will call `onCreate` callback
    // the other ones will call `onUpdate` callback
    if (!this.state.isCreated) {
      this.state.isCreated = true;
      this.options.onCreate(data);
    } else {
      this.options.onUpdate(data);
    }
  }

  /**
   * Helper used to know if the given modifier is enabled.