function update()

in js/popper.js [920:964]


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);
  }
}