servo/tests/wpt/web-platform-tests/css/cssom-view/resources/matchMedia.js

45 lines
1.3 KiB
JavaScript

const IFRAME_DEFAULT_SIZE = "200";
const iframes = new WeakMap();
async function createMQL(t) {
const iframe = await createIFrame(t);
const mql = iframe.contentWindow.matchMedia(`(max-width: ${IFRAME_DEFAULT_SIZE}px)`);
assert_true(mql.matches, "MQL should match on newly created <iframe>");
iframes.set(mql, iframe);
return mql;
}
function createIFrame(t, width = IFRAME_DEFAULT_SIZE, height = width) {
assert_not_equals(document.body, null, "<body> element is missing");
const iframe = document.createElement("iframe");
iframe.srcdoc = "";
iframe.width = String(width);
iframe.height = String(height);
iframe.style.border = "none";
t.add_cleanup(() => {
document.body.removeChild(iframe);
});
return new Promise(resolve => {
iframe.addEventListener("load", () => {
iframe.contentDocument.body.offsetWidth; // reflow
resolve(iframe);
});
document.body.appendChild(iframe);
});
}
function triggerMQLEvent(mql) {
const iframe = iframes.get(mql);
assert_not_equals(iframe, undefined, "Passed MQL instance was not created with createMQL");
iframe.width = iframe.width === IFRAME_DEFAULT_SIZE ? "250" : IFRAME_DEFAULT_SIZE;
}
function waitForChangesReported() {
return new Promise(resolve => {
step_timeout(resolve, 75);
});
}