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<!DOCTYPE html>
<meta charset="utf-8">
<title>Append child writable stream demo</title>
<script src="transforms/transform-stream-polyfill.js"></script>
<script src="transforms/text-encode-transform.js"></script>
<script src="transforms/parse-json.js"></script>
<script src="transforms/split-stream.js"></script>
<script src="resources/highlight.pack.js"></script>
<script src="resources/web-animations.min.js"></script>
<script src="tags/view-source.js"></script>
<link rel=stylesheet href="resources/common.css">
<link rel=stylesheet href="resources/commits.css">
<h1>Append child writable stream demo</h1>
<a id=back-to-index href=index.html>Back to demo index</a>
<view-source></view-source>
<div id=buttons>
<button id="load">Load JSON stream</button>
<button id="reset">Reset</button>
</div>
<div id=target></div>
<script>
'use strict';
const loadButton = document.querySelector('#load');
const resetButton = document.querySelector('#reset');
const targetDiv = document.querySelector('#target');
const FIELDS = ['Hash', 'Date', 'Author', 'Subject'];
const FIELDS_LOWERCASE = FIELDS.map(string => string.toLowerCase());
function createTable(parentElement) {
const table = document.createElement('table');
table.id = 'commits';
const tr = document.createElement('tr');
for (const heading of FIELDS) {
const th = document.createElement('th');
th.textContent = heading;
tr.appendChild(th);
}
table.appendChild(tr);
parentElement.appendChild(table);
return table;
}
// BEGIN SOURCE TO VIEW
function appendChildWritableStream(parentNode) {
return new WritableStream({
write(chunk) {
parentNode.appendChild(chunk);
}
});
}
async function fetchThenJSONToDOM() {
const jsonToElementTransform = new TransformStream({
transform(chunk, controller) {
const tr = document.createElement('tr');
for (const cell of FIELDS_LOWERCASE) {
const td = document.createElement('td');
td.textContent = chunk[cell];
tr.appendChild(td);
}
controller.enqueue(tr);
}
});
const response = await fetch('data/commits.json',
{
mode: 'same-origin',
headers: {
'Cache-Control': 'no-cache, no-store'
}
});
const table = createTable(targetDiv);
return response.body
.pipeThrough(new TextDecoder())
.pipeThrough(splitStream('\n'))
.pipeThrough(parseJSON())
.pipeThrough(jsonToElementTransform)
.pipeTo(appendChildWritableStream(table));
}
// END SOURCE TO VIEW
loadButton.onclick = () => {
loadButton.disabled = true;
setTimeout(fetchThenJSONToDOM, 0);
};
resetButton.onclick = () => {
targetDiv.innerHTML = '';
loadButton.disabled = false;
};
</script>