Beautify JSON display in browser
// ==UserScript==
// @name JSON Viewer
// @namespace https://github.com/EastSun5566
// @version 0.0.1
// @description Beautify JSON display in browser
// @author Michael Wang
// @license MIT
// @match *://*/*
// @grant GM_addStyle
// @run-at document-end
// ==/UserScript==
// @ts-check
/* eslint-disable no-alert */
/** @param {string} text */
function escapeHtml(text) {
const div = document.createElement('div');
div.textContent = text;
return div.innerHTML;
}
/** @param {unknown} data */
function renderJSON(data, indent = 0) {
const indentStr = ' '.repeat(indent);
let html = '';
if (Array.isArray(data)) {
if (data.length === 0) {
return '<span class="json-bracket">[]</span>';
}
const id = `arr_${Math.random().toString(36).slice(2, 9)}`;
html += `<span class="json-toggle" data-target="${id}">▼</span>`;
html += '<span class="json-bracket">[</span>\n';
html += `<div id="${id}" class="json-collapsible">`;
data.forEach((item, i) => {
html += `${indentStr} `;
html += renderJSON(item, indent + 1);
if (i < data.length - 1) {
html += '<span class="json-comma">,</span>';
}
html += '\n';
});
html += '</div>';
html += `${indentStr}<span class="json-bracket">]</span>`;
} else if (typeof data === 'object' && data !== null) {
const keys = Object.keys(data);
if (keys.length === 0) {
return '<span class="json-bracket">{}</span>';
}
const id = `obj_${Math.random().toString(36).slice(2, 9)}`;
html += `<span class="json-toggle" data-target="${id}">▼</span>`;
html += '<span class="json-bracket">{</span>\n';
html += `<div id="${id}" class="json-collapsible">`;
keys.forEach((key, i) => {
html += `${indentStr} `;
html += `<span class="json-key">"${escapeHtml(key)}"</span>: `;
html += renderJSON(data[key], indent + 1);
if (i < keys.length - 1) {
html += '<span class="json-comma">,</span>';
}
html += '\n';
});
html += '</div>';
html += `${indentStr}<span class="json-bracket">}</span>`;
} else if (typeof data === 'string') {
html += `<span class="json-string">"${escapeHtml(data)}"</span>`;
} else if (typeof data === 'number') {
html += `<span class="json-number">${data}</span>`;
} else if (typeof data === 'boolean') {
html += `<span class="json-boolean">${data}</span>`;
} else if (data === null) {
html += '<span class="json-null">null</span>';
}
return html;
}
(function () {
const contentType = document.contentType || '';
const isJSONContentType = contentType.includes('application/json');
/** @type {HTMLPreElement | null} */
const pre = document.querySelector('body > pre');
const bodyText = document.body?.innerText?.trim();
if (!pre && !isJSONContentType) return;
const jsonText = pre?.innerText || bodyText || '';
if (!jsonText) return;
let jsonData;
try {
jsonData = JSON.parse(jsonText);
} catch (e) {
return;
}
document.body.innerHTML = '';
// @ts-ignore
// eslint-disable-next-line no-undef
GM_addStyle(`
* {
margin: 0;
padding: 0;
box-sizing: border-box;
}
body {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
font-size: 14px;
line-height: 1.5;
color: #333;
background: #fff;
padding: 20px;
}
@media (prefers-color-scheme: dark) {
body {
background: #1e1e1e;
color: #d4d4d4;
}
.json-key { color: #9cdcfe !important; }
.json-string { color: #ce9178 !important; }
.json-number { color: #b5cea8 !important; }
.json-boolean { color: #569cd6 !important; }
.json-null { color: #569cd6 !important; }
.json-toggle { color: #d4d4d4 !important; }
.toolbar { background: #252526 !important; border-color: #3e3e42 !important; }
.toolbar button {
background: #3e3e42 !important;
color: #d4d4d4 !important;
border-color: #555 !important;
}
.toolbar button:hover { background: #505050 !important; }
}
.toolbar {
position: sticky;
top: 0;
background: #f5f5f5;
padding: 10px;
border-bottom: 1px solid #ddd;
margin: -20px -20px 20px -20px;
display: flex;
gap: 10px;
align-items: center;
z-index: 1000;
}
.toolbar button {
padding: 6px 12px;
border: 1px solid #ccc;
border-radius: 4px;
background: #fff;
cursor: pointer;
font-size: 13px;
}
.toolbar button:hover {
background: #e9e9e9;
}
.json-container {
font-family: "Monaco", "Menlo", "Consolas", monospace;
white-space: pre-wrap;
word-wrap: break-word;
}
.json-line {
padding-left: 20px;
}
.json-key {
color: #881391;
font-weight: 500;
}
.json-string {
color: #c41a16;
}
.json-number {
color: #1c00cf;
}
.json-boolean {
color: #0d22aa;
font-weight: bold;
}
.json-null {
color: #808080;
font-style: italic;
}
.json-toggle {
cursor: pointer;
user-select: none;
color: #666;
display: inline-block;
width: 16px;
font-weight: bold;
}
.json-toggle:hover {
color: #000;
}
.json-collapsed {
display: none;
}
.json-bracket {
color: #666;
font-weight: bold;
}
.json-comma {
color: #666;
}
`);
const toolbar = document.createElement('div');
toolbar.className = 'toolbar';
toolbar.innerHTML = `
<button id="expandAll">Expand All</button>
<button id="collapseAll">Collapse All</button>
<button id="copyJson">Copy JSON</button>
<button id="downloadJson">Download</button>
<span style="margin-left: auto; font-size: 12px; color: #666;">
${Object.keys(jsonData).length} keys
</span>
`;
const container = document.createElement('div');
container.className = 'json-container';
document.body.appendChild(toolbar);
document.body.appendChild(container);
container.innerHTML = renderJSON(jsonData);
// collapse/expand
container.addEventListener('click', (e) => {
const toggle = e.target.closest('.json-toggle');
if (!toggle) return;
const targetId = toggle.dataset.target;
const target = document.getElementById(targetId);
if (!target) return;
if (target.classList.contains('json-collapsed')) {
target.classList.remove('json-collapsed');
toggle.textContent = '▼';
} else {
target.classList.add('json-collapsed');
toggle.textContent = '▶';
}
});
// toolbar buttons
document.getElementById('expandAll')?.addEventListener('click', () => {
document.querySelectorAll('.json-collapsible').forEach((el) => {
el.classList.remove('json-collapsed');
});
document.querySelectorAll('.json-toggle').forEach((el) => {
el.textContent = '▼';
});
});
document.getElementById('collapseAll')?.addEventListener('click', () => {
document.querySelectorAll('.json-collapsible').forEach((el) => {
el.classList.add('json-collapsed');
});
document.querySelectorAll('.json-toggle').forEach((el) => {
el.textContent = '▶';
});
});
document.getElementById('copyJson')?.addEventListener('click', () => {
navigator.clipboard.writeText(JSON.stringify(jsonData, null, 2))
.then(() => alert('JSON copied to clipboard!'))
.catch((error) => alert(`Failed to copy: ${error}`));
});
document.getElementById('downloadJson')?.addEventListener('click', () => {
const blob = new Blob([JSON.stringify(jsonData, null, 2)], {
type: 'application/json',
});
const url = URL.createObjectURL(blob);
const a = document.createElement('a');
a.href = url;
let filename = window.location.pathname.split('/').pop() || 'download';
if (!/\.json$/.test(filename)) {
filename += '.json';
}
a.download = filename;
a.click();
URL.revokeObjectURL(url);
});
}());