Bindings for IntersectionObserver

CHANGELOG.md

@@ -5,6 +5,7 @@ Done:
 * Remove deprecated APIs
 * `Window.getSelection` now returns an option, to better match the definition
 * Add scrollToWithOptions to window
+* Added IntersectionObserver and IntersectionObserverEntry bindings
 
 Todo:
 * Convert to rescript syntax

lib/js/tests/Webapi/Webapi__IntersectionObserver__test.js

@@ -0,0 +1,49 @@
+'use strict';
+
+var Belt_Option = require("rescript/lib/js/belt_Option.js");
+var Caml_option = require("rescript/lib/js/caml_option.js");
+var TestHelpers = require("../testHelpers.js");
+var Webapi__Dom__Document = require("../../src/Webapi/Dom/Webapi__Dom__Document.js");
+
+var el = document.createElement("div");
+
+var body = TestHelpers.unsafelyUnwrapOption(Belt_Option.flatMap(Webapi__Dom__Document.asHtmlDocument(document), (function (prim) {
+            return Caml_option.nullable_to_opt(prim.body);
+          })));
+
+el.innerText = "Hello There";
+
+el.setAttribute("style", "margin-top: 800px; margin-bottom: 800px");
+
+body.appendChild(el);
+
+function handler(entries, observer) {
+  entries.forEach(function (entry) {
+        console.log(entry.time);
+        console.log(entry.rootBounds);
+        console.log(entry.boundingClientRect);
+        console.log(entry.intersectionRect);
+        console.log(entry.isIntersecting);
+        console.log(entry.intersectionRatio);
+        console.log(entry.target);
+
+      });
+  observer.unobserve(el);
+
+}
+
+var observer = new IntersectionObserver(handler);
+
+observer.observe(el);
+
+observer.unobserve(el);
+
+observer.observe(el);
+
+observer.disconnect();
+
+exports.el = el;
+exports.body = body;
+exports.handler = handler;
+exports.observer = observer;
+/* el Not a pure module */

src/Webapi.res

@@ -26,6 +26,7 @@ module Performance = Webapi__Performance
 /** @since 0.19.0 */
 module ReadableStream = Webapi__ReadableStream
 
+module IntersectionObserver = Webapi__IntersectionObserver
 module ResizeObserver = Webapi__ResizeObserver
 module Url = Webapi__Url
 

src/Webapi/Webapi__IntersectionObserver.res

@@ -0,0 +1,61 @@
+/**
+ * Spec: https://www.w3.org/TR/intersection-observer/
+ */
+
+module IntersectionObserverEntry = {
+  /**
+   * Spec: https://www.w3.org/TR/intersection-observer/#intersection-observer-entry
+   */
+
+  type t = Dom.intersectionObserverEntry
+
+  /* Properties */
+
+  @get external time: t => float = "time"
+  @get external rootBounds: t => Dom.domRect = "rootBounds"
+  @get external boundingClientRect: t => Dom.domRect = "boundingClientRect"
+  @get external intersectionRect: t => Dom.domRect = "intersectionRect"
+  @get external isIntersecting: t => bool = "isIntersecting"
+  @get external intersectionRatio: t => float = "intersectionRatio"
+  @get external target: t => Dom.element = "target"
+}
+
+type t = Dom.intersectionObserver
+
+type intersectionObserverInit = {
+  root: option<Dom.element>,
+  rootMargin: option<string>,
+  threshold: option<array<float>>, // between 0 and 1.
+}
+
+@obj
+external makeInit: (
+  ~root: Dom.element=?,
+  ~rootMargin: string=?,
+  ~threshold: array<float>=?,
+  unit,
+) => intersectionObserverInit = ""
+
+@new
+external make: (@uncurry (array<IntersectionObserverEntry.t>, t) => unit) => t =
+  "IntersectionObserver"
+
+@new
+external makeWithInit: (
+  @uncurry (array<IntersectionObserverEntry.t>, t) => unit,
+  intersectionObserverInit,
+) => t = "IntersectionObserver"
+
+/* Properties */
+
+@get @return(nullable)
+external root: t => option<Dom.element> = "root"
+@get external rootMargin: t => string = "rootMargin"
+@get external thresholds: t => array<float> = "thresholds"
+
+/* Methods */
+
+@send external disconnect: t => unit = "disconnect"
+@send external observe: (t, Dom.element) => unit = "observe"
+@send external unobserve: (t, Dom.element) => unit = "unobserve"
+@send external takeRecords: t => array<IntersectionObserverEntry.t> = "takeRecords"

tests/Webapi/Webapi__IntersectionObserver__test.res

@@ -0,0 +1,31 @@
+let el = Webapi.Dom.document -> Webapi.Dom.Document.createElement("div")
+
+let body =
+  Webapi.Dom.Document.asHtmlDocument(Webapi.Dom.document)
+  ->Belt.Option.flatMap(Webapi.Dom.HtmlDocument.body)
+  ->TestHelpers.unsafelyUnwrapOption
+
+Webapi.Dom.Element.setInnerText(el, "Hello There")
+Webapi.Dom.Element.setAttribute(el, "style", "margin-top: 800px; margin-bottom: 800px")
+Webapi.Dom.Element.appendChild(body, el)
+
+let handler = (entries, observer) => {
+  Js.Array.forEach(entry => {
+    Js.log(Webapi.IntersectionObserver.IntersectionObserverEntry.time(entry))
+    Js.log(Webapi.IntersectionObserver.IntersectionObserverEntry.rootBounds(entry))
+    Js.log(Webapi.IntersectionObserver.IntersectionObserverEntry.boundingClientRect(entry))
+    Js.log(Webapi.IntersectionObserver.IntersectionObserverEntry.intersectionRect(entry))
+    Js.log(Webapi.IntersectionObserver.IntersectionObserverEntry.isIntersecting(entry))
+    Js.log(Webapi.IntersectionObserver.IntersectionObserverEntry.intersectionRatio(entry))
+    Js.log(Webapi.IntersectionObserver.IntersectionObserverEntry.target(entry))
+  }, entries)
+
+  Webapi.IntersectionObserver.unobserve(observer, el)
+}
+
+let observer = Webapi.IntersectionObserver.make(handler)
+
+Webapi.IntersectionObserver.observe(observer, el)
+Webapi.IntersectionObserver.unobserve(observer, el)
+Webapi.IntersectionObserver.observe(observer, el)
+Webapi.IntersectionObserver.disconnect(observer)