MediaWiki:Gadget-blame.js - Revision history

Kai: Created page with "/* * Gadget: Blame — git blame for articles. Colours every word by the editor who * last changed it; words a template or module produced are hatched instead. * --> https://starcitizen.tools/index.php?title=MediaWiki:Gadget-blame.js&action=edit <-- * Special:Export/?history=1 is the transport because the Action API's * 50-row content cap does not apply there and $wgExportMaxHistory is not * consulted for GET. It also costs the server about a third of what th..."

2026-09-05T10:05:44Z

Created page with "/* * Gadget: Blame — git blame for articles. Colours every word by the editor who * last changed it; words a template or module produced are hatched instead. * --> https://starcitizen.tools/index.php?title=MediaWiki:Gadget-blame.js&action=edit <-- * Special:Export/<page>?history=1 is the transport because the Action API's * 50-row content cap does not apply there and $wgExportMaxHistory is not * consulted for GET. It also costs the server about a third of what th..."

New page

/*
* Gadget: Blame — git blame for articles. Colours every word by the editor who
* last changed it; words a template or module produced are hatched instead.
* --> https://starcitizen.tools/index.php?title=MediaWiki:Gadget-blame.js&action=edit <--
* Special:Export/<page>?history=1 is the transport because the Action API's
* 50-row content cap does not apply there and $wgExportMaxHistory is not
* consulted for GET. It also costs the server about a third of what the obvious
* alternative does: paging content by revision id spends more total server time
* and spreads it over ten requests instead of one. A wiki with
* $wgExportAllowHistory=false returns ONE revision rather than an error, hence
* the fallback to prop=revisions.
*
* Parsoid is never consulted. Its source offsets cannot attribute template
* parameter prose or the reference list, and its HTML can carry unexpanded
* {{#parsoidfragment}} markers (T432547).
*
* Codex components are avoided for bundle size: the chrome is this gadget's own
* CSS over Codex design tokens, and the popover is the platform's own.
*/
( function () {
'use strict';

const text = require( './blame-text.js' );
const teleportTarget = require( 'mediawiki.page.ready' ).teleportTarget;

// Time-based, not every N revisions: per-revision cost varies by orders of
// magnitude, so a fixed count still leaves 50 ms+ tasks.
const SLICE_MS = 16;
const PALETTE_SIZE = 8;
const HIDDEN = '(hidden)';
// Past the cap the unmatched middle is credited to the newer revision, so a
// cap below a plausible scattered sweep hands one editor text they never
// wrote. Myers costs O(cap^2) once exhausted.
const MAX_D_REVISION = 5000;
// Page-to-source diverges much further, since template output has no source
// counterpart at all: 3565 measured on an infobox fed from an API. Exhausting
// this hatches the WHOLE page rather than the excess.
const MAX_D_ALIGN = 20000;
// <style> is here because TemplateStyles injects it inside .mw-parser-output.
// The reference LIST is deliberately absent: moveRefs makes it attributable.
//
// Template classes must NOT be added. Their parameter values stay in the
// source stream, and the alignment is a monotone LCS, so excluding the
// rendered region strands those tokens for the first body word that matches.
const UNPAINTED = '.mw-editsection, sup.reference, .mw-cite-backlink, style, script, .gadget-blame-popover, .gadget-blame-legend';
// cdxIconClose, inlined: @wikimedia/codex-icons is not a ResourceLoader module.
const ICON_CLOSE = 'M16.707 4.707 11.414 10l5.293 5.293-1.414 1.414L10 11.414l-5.293 5.293-1.414-1.414L8.586 10 3.293 4.707l1.414-1.414L10 8.586l5.293-5.293z';

const config = mw.config.get( [
'wgIsArticle', 'wgArticleId', 'wgAction', 'wgPageName', 'wgRevisionId',
'wgCurRevisionId'
] );
if ( !config.wgIsArticle || !config.wgArticleId || config.wgAction !== 'view' ) {
return;
}

let historyPromise = null;
const page = { on: false, token: 0, painted: [], legend: null, revById: null };

function el( tag, attrs, children ) {
const node = document.createElement( tag );
Object.keys( attrs || {} ).forEach( ( k ) => {
if ( k === 'class' ) {
node.className = attrs[ k ];
} else if ( k === 'text' ) {
node.textContent = attrs[ k ];
} else {
node.setAttribute( k, attrs[ k ] );
}
} );
( children || [] ).forEach( ( c ) => {
if ( c ) {
node.appendChild( typeof c === 'string' ? document.createTextNode( c ) : c );
}
} );
return node;
}

function link( href, label, cls ) {
return el( 'a', { href, class: cls || '', text: label } );
}

function iconButton( label, pathD ) {
const svgNs = 'http://www.w3.org/2000/svg';
const svg = document.createElementNS( svgNs, 'svg' );
svg.setAttribute( 'width', '20' );
svg.setAttribute( 'height', '20' );
svg.setAttribute( 'viewBox', '0 0 20 20' );
svg.setAttribute( 'aria-hidden', 'true' );
const path = document.createElementNS( svgNs, 'path' );
path.setAttribute( 'd', pathD );
svg.appendChild( path );
return el( 'button', {
type: 'button',
class: 'gadget-blame__button',
'aria-label': label,
title: label
}, [ svg ] );
}

function message( type, children ) {
return el( 'div', {
class: 'gadget-blame__notice gadget-blame__notice--' + type,
'aria-live': 'polite'
}, children );
}

function formatDate( iso ) {
const d = new Date( iso );
return isNaN( d ) ? iso : d.toLocaleString( undefined, { dateStyle: 'medium', timeStyle: 'short' } );
}

function userLink( name ) {
if ( !name ) {
return el( 'span', { class: 'gadget-blame__meta', text: HIDDEN } );
}
const isIp = mw.util.isIPAddress ? mw.util.isIPAddress( name ) : /^\d+\.\d+\.\d+\.\d+$/.test( name );
const target = isIp ? 'Special:Contributions/' + name : 'User:' + name;
return link( mw.util.getUrl( target ), name, 'gadget-blame__user' );
}

function contentRoot() {
return document.querySelector( '#mw-content-text .mw-parser-output' );
}

function tick() {
return new Promise( ( resolve ) => setTimeout( resolve ) );
}

function textOf( parent, selector ) {
const n = parent.querySelector( selector );
return n ? n.textContent : '';
}

function parseExport( xml ) {
const doc = new DOMParser().parseFromString( xml, 'application/xml' );
if ( doc.querySelector( 'parsererror' ) ) {
throw new Error( 'blame-export-parse' );
}
const revs = [];
doc.querySelectorAll( 'revision' ).forEach( ( r ) => {
const t = r.querySelector( ':scope > text' );
const hidden = !t || t.getAttribute( 'deleted' ) === 'deleted';
revs.push( {
id: Number( textOf( r, ':scope > id' ) ),
parentid: Number( textOf( r, ':scope > parentid' ) || 0 ),
timestamp: textOf( r, ':scope > timestamp' ),
user: textOf( r, ':scope > contributor > username' ) || textOf( r, ':scope > contributor > ip' ),
comment: textOf( r, ':scope > comment' ),
sha1: textOf( r, ':scope > sha1' ) || ( t && t.getAttribute( 'sha1' ) ) || '',
// null, not '': revision-deleted text is excluded, not an empty page.
text: hidden ? null : t.textContent
} );
} );
revs.sort( ( a, b ) => ( a.timestamp < b.timestamp ? -1 : a.timestamp > b.timestamp ? 1 : a.id - b.id ) );
return revs;
}

function fetchExport() {
const url = mw.util.getUrl( 'Special:Export/' + config.wgPageName, { history: 1 } );
return fetch( url, { credentials: 'same-origin' } ).then( ( r ) => {
if ( !r.ok ) {
throw new Error( 'blame-export-http-' + r.status );
}
return r.text();
} ).then( parseExport );
}

function fetchViaApi() {
const api = new mw.Api();
const revs = [];
function batch( cont ) {
const params = Object.assign( {
action: 'query',
prop: 'revisions',
titles: config.wgPageName,
rvprop: 'ids|timestamp|user|comment|sha1|content',
rvslots: 'main',
rvlimit: 50,
rvdir: 'newer',
formatversion: 2
}, cont || {} );
return api.get( params ).then( ( data ) => {
const p = data.query.pages[ 0 ];
( p.revisions || [] ).forEach( ( r ) => {
const slot = r.slots && r.slots.main;
revs.push( {
id: r.revid,
parentid: r.parentid || 0,
timestamp: r.timestamp,
user: r.user || '',
comment: r.comment || '',
sha1: r.sha1 || '',
text: slot && !slot.texthidden && !r.texthidden &&
typeof slot.content === 'string' ? slot.content : null
} );
} );
return data.continue ? batch( data.continue ) : revs;
} );
}
return batch();
}

function loadHistory() {
if ( !historyPromise ) {
historyPromise = fetchExport()
.catch( fetchViaApi )
.then( ( revs ) => (
// $wgExportAllowHistory=false: a one-revision export with a parent.
revs.length === 1 && revs[ 0 ].parentid > 0 ? fetchViaApi() : revs
) )
.catch( ( e ) => {
historyPromise = null;
throw e;
} );
}
return historyPromise;
}

function setBody( body, children ) {
body.textContent = '';
children.forEach( ( c ) => c && body.appendChild( c ) );
}

function loading( body, label ) {
setBody( body, [
el( 'div', { class: 'gadget-blame__bar', role: 'progressbar', 'aria-label': label } ),
el( 'div', { class: 'gadget-blame__meta', text: label } )
] );
}

function renderError( body, err ) {
setBody( body, [ message( 'error', [
'Could not load the page history (' + ( err && err.message ? err.message : 'unknown error' ) + ').'
] ) ] );
}

// The popover attribute gives light dismissal, Escape and the top layer. Only
// placement is ours: CSS anchor positioning would do it declaratively but is
// not yet in Firefox or Safari.
let popoverEl = null;
let popoverAnchor = null;

function setActive( on ) {
if ( popoverAnchor ) {
popoverAnchor.classList.toggle( 'gadget-blame-w--active', on );
}
}

function place() {
if ( !popoverEl || !popoverAnchor ) {
return;
}
const gap = 8;
const a = popoverAnchor.getBoundingClientRect();
const p = popoverEl.getBoundingClientRect();
let top = a.bottom + gap;
if ( top + p.height > window.innerHeight - gap && a.top - gap - p.height > gap ) {
top = a.top - gap - p.height;
}
const left = Math.max( gap, Math.min( a.left, window.innerWidth - p.width - gap ) );
popoverEl.style.top = Math.max( gap, top ) + 'px';
popoverEl.style.left = left + 'px';
}

function hidePopover() {
if ( !popoverEl ) {
return;
}
if ( popoverEl.hidePopover ) {
if ( popoverEl.matches( ':popover-open' ) ) {
popoverEl.hidePopover();
}
} else {
popoverEl.classList.remove( 'gadget-blame-popover--open' );
}
setActive( false );
popoverAnchor = null;
}

function ensurePopoverEl() {
if ( popoverEl ) {
return popoverEl;
}
popoverEl = el( 'div', { class: 'gadget-blame-popover', role: 'dialog', 'aria-label': 'Revision' } );
if ( 'popover' in popoverEl ) {
popoverEl.setAttribute( 'popover', 'auto' );
// Light dismissal bypasses hidePopover, so the ring is cleared here.
popoverEl.addEventListener( 'toggle', ( e ) => {
if ( e.newState === 'closed' ) {
setActive( false );
popoverAnchor = null;
}
} );
} else {
document.addEventListener( 'click', ( e ) => {
if ( popoverAnchor && !popoverEl.contains( e.target ) && !e.target.closest( '.gadget-blame-w' ) ) {
hidePopover();
}
} );
document.addEventListener( 'keydown', ( e ) => {
if ( e.key === 'Escape' && popoverAnchor ) {
hidePopover();
}
} );
}
// The anchor is inline text, so it moves with the page.
window.addEventListener( 'scroll', place, true );
window.addEventListener( 'resize', place );
teleportTarget.appendChild( popoverEl );
return popoverEl;
}

function card( rev ) {
if ( !rev ) {
return [ message( 'notice', [ 'Not written on this page — template or module output.' ] ) ];
}
const isIp = mw.util.isIPAddress ? mw.util.isIPAddress( rev.user ) : false;
const who = rev.user ?
link( mw.util.getUrl( ( isIp ? 'Special:Contributions/' : 'User:' ) + rev.user ), rev.user, 'gadget-blame__user' ) :
el( 'span', { class: 'gadget-blame__meta', text: HIDDEN } );
return [ el( 'div', { class: 'gadget-blame__card' }, [
el( 'div', { class: 'gadget-blame__date', text: formatDate( rev.timestamp ) } ),
el( 'div', null, [ who ] ),
rev.comment ? el( 'div', { class: 'gadget-blame__summary', text: rev.comment } ) : null,
el( 'div', { class: 'gadget-blame__links' }, [
link( mw.util.getUrl( 'Special:Diff/' + rev.id ), 'Diff' ),
link( mw.util.getUrl( 'Special:PermanentLink/' + rev.id ), 'Revision ' + rev.id )
] )
] ) ];
}

function showPopover( anchor, rev ) {
const node = ensurePopoverEl();
setActive( false );
popoverAnchor = anchor;
setBody( node, card( rev ) );
if ( node.showPopover ) {
if ( node.matches( ':popover-open' ) ) {
node.hidePopover();
}
node.showPopover();
} else {
node.classList.add( 'gadget-blame-popover--open' );
}
setActive( true );
place();
}

// Text is gathered per block so a word split across inline markup
// ("<i>Title</i>'s") is tokenised whole rather than as three fragments.
const BLOCKS = 'address, article, aside, blockquote, caption, dd, details, dialog, div, dl, dt, fieldset, figcaption, figure, footer, form, h1, h2, h3, h4, h5, h6, header, hgroup, li, main, nav, ol, p, pre, section, summary, table, tbody, td, tfoot, th, thead, tr, ul';

// A word straddling an inline element has more than one text-node range.
function renderedTokens( root ) {
const walker = document.createTreeWalker( root, NodeFilter.SHOW_TEXT, {
acceptNode: ( n ) => {
const p = n.parentElement;
return p && !p.closest( UNPAINTED ) ? NodeFilter.FILTER_ACCEPT : NodeFilter.FILTER_REJECT;
}
} );
const re = new RegExp( text.TOKEN_RE.source, text.TOKEN_RE.flags );
const out = [];
let block = null;
let joined = '';
let segments = [];

function flush() {
if ( !joined ) {
return;
}
re.lastIndex = 0;
let m;
let seg = 0;
while ( ( m = re.exec( joined ) ) ) {
const norm = text.normaliseText( m[ 0 ] );
if ( !norm ) {
continue;
}
const from = m.index;
const to = from + m[ 0 ].length;
while ( seg < segments.length && segments[ seg ].end <= from ) {
seg++;
}
const pieces = [];
for ( let i = seg; i < segments.length && segments[ i ].start < to; i++ ) {
const sgm = segments[ i ];
pieces.push( {
node: sgm.node,
start: Math.max( from, sgm.start ) - sgm.start,
end: Math.min( to, sgm.end ) - sgm.start
} );
}
out.push( { pieces, norm } );
}
joined = '';
segments = [];
}

let n;
while ( ( n = walker.nextNode() ) ) {
const owner = n.parentElement.closest( BLOCKS ) || root;
if ( owner !== block ) {
flush();
block = owner;
}
segments.push( { node: n, start: joined.length, end: joined.length + n.nodeValue.length } );
joined += n.nodeValue;
}
flush();
return out;
}

// One replacement per text node; the original is kept for unpaint().
function paint( tokens, classify ) {
// A span cannot straddle text nodes, so a word split across inline markup
// is painted once per node, each piece carrying the same origin.
const byNode = new Map();
tokens.forEach( ( t, k ) => {
const c = classify( k );
t.pieces.forEach( ( piece ) => {
if ( !byNode.has( piece.node ) ) {
byNode.set( piece.node, [] );
}
byNode.get( piece.node ).push( { start: piece.start, end: piece.end, c } );
} );
} );
byNode.forEach( ( pieces, node ) => {
const s = node.nodeValue;
const frag = document.createDocumentFragment();
const added = [];
let pos = 0;
let k = 0;
while ( k < pieces.length ) {
const c = pieces[ k ].c;
const key = c ? c.rev : -1;
const start = pieces[ k ].start;
let end = pieces[ k ].end;
let next = k + 1;
while ( next < pieces.length ) {
const cn = pieces[ next ].c;
if ( ( cn ? cn.rev : -1 ) !== key ) {
break;
}
end = pieces[ next ].end;
next++;
}
if ( start > pos ) {
added.push( frag.appendChild( document.createTextNode( s.slice( pos, start ) ) ) );
}
const span = el( 'span', {
class: 'gadget-blame-w ' + ( c ? 'gadget-blame-a' + c.cls : 'gadget-blame-w--template' ),
text: s.slice( start, end )
} );
if ( c ) {
span.setAttribute( 'data-gadget-blame-revid', String( c.rev ) );
// So attribution is not carried by colour alone.
span.setAttribute( 'title', c.who );
}
added.push( frag.appendChild( span ) );
pos = end;
k = next;
}
if ( pos < s.length ) {
added.push( frag.appendChild( document.createTextNode( s.slice( pos ) ) ) );
}
node.parentNode.replaceChild( frag, node );
page.painted.push( { original: node, pieces: added } );
} );
}

// Roving tabindex: thousands of tab stops would make the article unusable.
// The runs deliberately carry no role either — one would make a screen reader
// announce every phrase as a control instead of reading it as prose.
function runs() {
const root = contentRoot();
return root ? Array.from( root.querySelectorAll( '.gadget-blame-w' ) ) : [];
}

function setTabStop( run ) {
runs().forEach( ( r ) => r.setAttribute( 'tabindex', r === run ? '0' : '-1' ) );
}

function moveTabStop( from, delta ) {
const all = runs();
const i = all.indexOf( from );
const next = all[ Math.min( all.length - 1, Math.max( 0, ( i < 0 ? 0 : i ) + delta ) ) ];
if ( next ) {
setTabStop( next );
next.focus();
next.scrollIntoView( { block: 'nearest' } );
}
return next;
}

function unpaint() {
page.painted.forEach( ( p ) => {
const first = p.pieces[ 0 ];
if ( first && first.parentNode ) {
first.parentNode.insertBefore( p.original, first );
}
p.pieces.forEach( ( n ) => n.parentNode && n.parentNode.removeChild( n ) );
} );
page.painted = [];
}

function closeLegend() {
if ( page.legend ) {
page.legend.remove();
page.legend = null;
}
}

function turnOff() {
page.token++;
page.on = false;
unpaint();
closeLegend();
page.revById = null;
hidePopover();
}

function openLegend() {
closeLegend();
const body = el( 'div', { class: 'gadget-blame__body' } );
const off = iconButton( 'Turn off', ICON_CLOSE );
off.addEventListener( 'click', turnOff );
page.legend = el( 'div', { class: 'gadget-blame-legend', role: 'region', 'aria-label': 'Blame legend' }, [
el( 'div', { class: 'gadget-blame__header' }, [
el( 'span', { class: 'gadget-blame__title', text: 'Blame' } ),
off
] ),
body
] );
teleportTarget.appendChild( page.legend );
return body;
}

function pct( n, total ) {
if ( !total || !n ) {
return '0%';
}
const p = Math.round( 100 * n / total );
return p === 0 ? '<1%' : p + '%';
}

function legendRow( swatchClass, label, share ) {
const labelNode = typeof label === 'string' ? el( 'span', { text: label } ) : label;
labelNode.classList.add( 'gadget-blame__label' );
return el( 'div', { class: 'gadget-blame__row' }, [
el( 'span', { class: 'gadget-blame-swatch ' + swatchClass } ),
labelNode,
el( 'span', { class: 'gadget-blame__meta', text: share } )
] );
}

function plural( n, word ) {
return n + ' ' + word + ( n === 1 ? '' : 's' );
}

function renderLegend( body, stats ) {
const rows = stats.authors.slice( 0, PALETTE_SIZE ).map( ( pair, idx ) => legendRow(
'gadget-blame-a' + idx,
userLink( pair[ 0 ] === HIDDEN ? '' : pair[ 0 ] ),
pct( pair[ 1 ], stats.total )
) );
const rest = stats.authors.slice( PALETTE_SIZE );
if ( rest.length ) {
const n = rest.reduce( ( sum, pair ) => sum + pair[ 1 ], 0 );
rows.push( legendRow( 'gadget-blame-ax', plural( rest.length, 'other editor' ), pct( n, stats.total ) ) );
}
if ( stats.template ) {
rows.push( legendRow( 'gadget-blame-w--template', 'Template output', pct( stats.template, stats.total ) ) );
}
const notes = [ plural( stats.revisions, 'revision' ) + ' blamed' ];
if ( stats.reused ) {
notes.push( plural( stats.reused, 'revision' ) + ' restored an earlier version' );
}
if ( stats.capped ) {
notes.push( plural( stats.capped, 'revision' ) + ' changed too much to trace word by word' );
}
if ( stats.gaps ) {
notes.push( 'text older than this history, or from a hidden revision, is credited to the oldest revision that shows it' );
}
if ( stats.alignCapped ) {
notes.push( 'this page and its source differ too much to line up, so nothing could be attributed' );
}
rows.push( el( 'div', {
class: 'gadget-blame__footer',
text: notes.join( '. ' ) + '. Click a word for its revision, or tab into the text and use the arrow keys.'
} ) );
setBody( body, rows );
}

// One revision at a time: only the previous token stream is ever needed, and
// holding every stream at once runs to hundreds of megabytes.
async function buildOrigins( revs, body, token ) {
const pageName = config.wgPageName.replace( /_/g, ' ' );
const blamer = text.makeBlamer(
text.duplicateSha1s( revs.map( ( r ) => r.sha1 ) ),
MAX_D_REVISION
);
const intern = text.makeInterner();
let reused = 0;
let slice = performance.now();
for ( let i = 0; i < revs.length; i++ ) {
const r = revs[ i ];
if ( blamer.reuse( r.sha1 ) ) {
reused++;
} else {
blamer.push( intern( text.tokenize( text.wikitextToText( r.text, { pageName } ) ) ), i, r.sha1 );
}
if ( performance.now() - slice > SLICE_MS ) {
loading( body, 'Blaming ' + ( i + 1 ) + ' of ' + revs.length + ' revisions…' );
await tick();
if ( token !== page.token ) {
return null;
}
slice = performance.now();
}
}
return { intern, origins: blamer.origins, stream: blamer.stream, capped: blamer.capped, reused };
}

async function blamePage() {
if ( page.on ) {
turnOff();
return;
}
const root = contentRoot();
if ( !root ) {
return;
}
page.on = true;
const token = ++page.token;
const body = openLegend();
loading( body, 'Fetching history…' );
try {
const all = await loadHistory();
if ( token !== page.token ) {
return;
}
const upTo = config.wgRevisionId || config.wgCurRevisionId || Infinity;
const visible = all.filter( ( r ) => r.id <= upTo );
const revs = visible.filter( ( r ) => r.text !== null );
if ( !revs.length ) {
setBody( body, [ message( 'warning', [ 'No readable revisions to blame on this page.' ] ) ] );
return;
}
// Text this history cannot account for: revisions hidden inside it, or a
// history not starting at the page's creation.
const gaps = ( visible.length - revs.length ) + ( revs[ 0 ].parentid > 0 ? 1 : 0 );
const built = await buildOrigins( revs, body, token );
if ( !built ) {
return;
}
const toks = renderedTokens( root );
const alignStats = {};
const norms = toks.map( ( t ) => t.norm );
const map = text.dropPunctuationOnlyRuns(
text.diffMap( built.stream, built.intern( norms ), MAX_D_ALIGN, alignStats ),
norms
);
const counts = new Map();
let aligned = 0;
for ( let k = 0; k < toks.length; k++ ) {
if ( map[ k ] >= 0 ) {
aligned++;
const u = revs[ built.origins[ map[ k ] ] ].user || HIDDEN;
counts.set( u, ( counts.get( u ) || 0 ) + 1 );
}
}
const authors = Array.from( counts.entries() ).sort( ( a, b ) => b[ 1 ] - a[ 1 ] );
const cls = new Map();
authors.forEach( ( pair, idx ) => cls.set( pair[ 0 ], idx < PALETTE_SIZE ? String( idx ) : 'x' ) );
page.revById = new Map( revs.map( ( r ) => [ r.id, r ] ) );
paint( toks, ( k ) => {
const w = map[ k ];
if ( w < 0 ) {
return null;
}
const r = revs[ built.origins[ w ] ];
return { cls: cls.get( r.user || HIDDEN ), rev: r.id, who: r.user || HIDDEN };
} );
setTabStop( toks.length ? contentRoot().querySelector( '.gadget-blame-w' ) : null );
renderLegend( body, {
authors,
total: toks.length,
template: toks.length - aligned,
revisions: revs.length,
reused: built.reused,
capped: built.capped,
alignCapped: !!alignStats.capped,
gaps
} );
// Tens of megabytes on a long history; only popover metadata is kept.
revs.forEach( ( r ) => {
r.text = null;
} );
historyPromise = null;
} catch ( err ) {
if ( token === page.token ) {
renderError( body, err );
}
}
}

function openRun( w ) {
setTabStop( w );
const id = w.getAttribute( 'data-gadget-blame-revid' );
showPopover( w, id === null ? null : page.revById.get( Number( id ) ) );
}

// While blame is on, a run inside a link opens its revision instead of
// following the link.
document.addEventListener( 'click', ( e ) => {
const w = page.on && e.target.closest && e.target.closest( '.gadget-blame-w' );
if ( !w ) {
return;
}
if ( w.closest( 'a' ) ) {
e.preventDefault();
}
openRun( w );
} );

document.addEventListener( 'keydown', ( e ) => {
const w = page.on && e.target.closest && e.target.closest( '.gadget-blame-w' );
if ( !w || e.altKey || e.ctrlKey || e.metaKey ) {
return;
}
if ( e.key === 'ArrowRight' || e.key === 'ArrowDown' ) {
e.preventDefault();
moveTabStop( w, 1 );
} else if ( e.key === 'ArrowLeft' || e.key === 'ArrowUp' ) {
e.preventDefault();
moveTabStop( w, -1 );
} else if ( e.key === 'Enter' || e.key === ' ' ) {
e.preventDefault();
openRun( w );
}
} );

const item = mw.util.addPortletLink( 'p-tb', '#', 'Blame this page', 'gadget-blame-page', 'Colour every word by the editor who last changed it' );
if ( item ) {
item.addEventListener( 'click', ( e ) => {
e.preventDefault();
blamePage();
} );
}
}() );