binding.startChild()

This method checks whether the binding should listen to the child; if it should and it hasn’t already started listening, then it will start listening to the child and update the parent in the queue provided when the binding was initialized.

import Bind from "can-bind";
import DefineMap from "can-define/map/map";
import value from "can-value";

const childMap = new DefineMap({childProp: "child value"});
const parentMap = new DefineMap({parentProp: "parent value"});

// Create the binding
const binding = new Bind({
  child: value.bind(childMap, "childProp"),
  parent: value.bind(parentMap, "parentProp")
});

// Turn on just the child listener
binding.startChild();