eslint: Prefer const in mediawiki.api

Change-Id: Id1ec60db0489dc9b082ed164e98b0a2a46f56054

8 files changed, 56 insertions, 70 deletions

diff --git a/resources/src/mediawiki.api/category.js b/resources/src/mediawiki.api/category.js
index 7d2038aae3f6..1b6a0c9c36d5 100644
--- a/resources/src/mediawiki.api/category.js
+++ b/resources/src/mediawiki.api/category.js
@@ -62,12 +62,10 @@
 
 			return apiPromise
 				.then( ( data ) => {
-					let page;
-
 					if ( !data.query || !data.query.pages ) {
 						return false;
 					}
-					page = data.query.pages[ 0 ];
+					const page = data.query.pages[ 0 ];
 					if ( !page.categories ) {
 						return false;
 					}
diff --git a/resources/src/mediawiki.api/edit.js b/resources/src/mediawiki.api/edit.js
index 77b5979d5d7e..8e75c7d13578 100644
--- a/resources/src/mediawiki.api/edit.js
+++ b/resources/src/mediawiki.api/edit.js
@@ -114,11 +114,11 @@
 		 * @return {jQuery.Promise} Edit API response
 		 */
 		edit: function ( title, transform ) {
-			let basetimestamp, curtimestamp,
-				api = this;
+			const api = this;
 
 			title = String( title );
 
+			let basetimestamp, curtimestamp;
 			return api.get( {
 				action: 'query',
 				prop: 'revisions',
@@ -128,18 +128,17 @@
 				curtimestamp: true
 			} )
 				.then( ( data ) => {
-					let page, revision;
 					if ( !data.query || !data.query.pages ) {
 						return $.Deferred().reject( 'unknown' );
 					}
-					page = data.query.pages[ 0 ];
+					const page = data.query.pages[ 0 ];
 					if ( !page || page.invalid ) {
 						return $.Deferred().reject( 'invalidtitle' );
 					}
 					if ( page.missing ) {
 						return $.Deferred().reject( 'nocreate-missing' );
 					}
-					revision = page.revisions[ 0 ];
+					const revision = page.revisions[ 0 ];
 					basetimestamp = revision.timestamp;
 					curtimestamp = data.curtimestamp;
 					return transform( {
diff --git a/resources/src/mediawiki.api/index.js b/resources/src/mediawiki.api/index.js
index 704c64aea405..1d61b4703108 100644
--- a/resources/src/mediawiki.api/index.js
+++ b/resources/src/mediawiki.api/index.js
@@ -14,7 +14,7 @@
 	 * @private
 	 * @type {mw.Api.Options}
 	 */
-	let defaultOptions;
+	let defaultOptions = null;
 
 	/**
 	 * @classdesc Interact with the MediaWiki API. `mw.Api` is a client library for
@@ -231,14 +231,13 @@
 		 *       {@link JSON.parse}.
 		 */
 		ajax: function ( parameters, ajaxOptions ) {
-			let token, requestIndex,
-				api = this,
-				apiDeferred = $.Deferred(),
-				xhr, key, formData;
+			const api = this,
+				apiDeferred = $.Deferred();
 
 			parameters = Object.assign( {}, this.defaults.parameters, parameters );
 			ajaxOptions = Object.assign( {}, this.defaults.ajax, ajaxOptions );
 
+			let token;
 			// Ensure that token parameter is last (per [[mw:API:Edit#Token]]).
 			if ( parameters.token ) {
 				token = parameters.token;
@@ -254,9 +253,9 @@
 				ajaxOptions.contentType === 'multipart/form-data'
 			) {
 
-				formData = new FormData();
+				const formData = new FormData();
 
-				for ( key in parameters ) {
+				for ( const key in parameters ) {
 					formData.append( key, parameters[ key ] );
 				}
 				// If we extracted a token parameter, add it back in.
@@ -286,7 +285,7 @@
 			}
 
 			// Make the AJAX request
-			xhr = $.ajax( ajaxOptions )
+			const xhr = $.ajax( ajaxOptions )
 				// If AJAX fails, reject API call with error code 'http'
 				// and the details in the second argument.
 				.fail( ( jqXHR, textStatus, exception ) => {
@@ -318,7 +317,7 @@
 					}
 				} );
 
-			requestIndex = this.requests.length;
+			const requestIndex = this.requests.length;
 			this.requests.push( xhr );
 			xhr.always( () => {
 				api.requests[ requestIndex ] = null;
@@ -350,14 +349,14 @@
 		 * @since 1.22
 		 */
 		postWithToken: function ( tokenType, params, ajaxOptions ) {
-			let api = this,
+			const api = this,
 				assertParams = {
 					assert: params.assert,
 					assertuser: params.assertuser
 				},
 				abortedPromise = $.Deferred().reject( 'http',
-					{ textStatus: 'abort', exception: 'abort' } ).promise(),
-				abortable,
+					{ textStatus: 'abort', exception: 'abort' } ).promise();
+			let abortable,
 				aborted;
 
 			return api.getToken( tokenType, assertParams ).then( ( token ) => {
diff --git a/resources/src/mediawiki.api/login.js b/resources/src/mediawiki.api/login.js
index 49c93d5bce1e..bde2f0ca44cf 100644
--- a/resources/src/mediawiki.api/login.js
+++ b/resources/src/mediawiki.api/login.js
@@ -8,17 +8,17 @@
 		 * @return {jQuery.Promise} See [post()]{@link mw.Api#post}
 		 */
 		login: function ( username, password ) {
-			let params, apiPromise, innerPromise,
-				api = this;
+			const api = this;
 
-			params = {
+			const params = {
 				action: 'login',
 				lgname: username,
 				lgpassword: password
 			};
 
-			apiPromise = api.post( params );
+			const apiPromise = api.post( params );
 
+			let innerPromise;
 			return apiPromise
 				.then( ( data ) => {
 					params.lgtoken = data.login.token;
diff --git a/resources/src/mediawiki.api/options.js b/resources/src/mediawiki.api/options.js
index 776595257bf5..4ef4ecd82b4f 100644
--- a/resources/src/mediawiki.api/options.js
+++ b/resources/src/mediawiki.api/options.js
@@ -39,15 +39,14 @@
 		 * @return {jQuery.Promise}
 		 */
 		saveOptions: function ( options, params ) {
-			let name, value, bundleable,
-				grouped = [],
-				promise;
+			const grouped = [];
 
 			// Logged-out users can't have user options; we can't depend on mw.user, that'd be circular
 			if ( mw.config.get( 'wgUserName' ) === null || mw.config.get( 'wgUserIsTemp' ) ) {
 				return $.Deferred().reject( 'notloggedin' ).promise();
 			}
 
+			let promise;
 			// If another options request to this API is pending, wait for it first
 			if (
 				saveOptionsRequests[ this.defaults.ajax.url ] &&
@@ -63,9 +62,10 @@
 				promise = $.Deferred().resolve();
 			}
 
-			for ( name in options ) {
-				value = options[ name ] === null ? null : String( options[ name ] );
+			for ( const name in options ) {
+				const value = options[ name ] === null ? null : String( options[ name ] );
 
+				let bundleable;
 				// Can we bundle this option, or does it need a separate request?
 				if ( this.defaults.useUS ) {
 					bundleable = name.indexOf( '=' ) === -1;
diff --git a/resources/src/mediawiki.api/parse.js b/resources/src/mediawiki.api/parse.js
index 617e499b59a3..2f0a0881a77c 100644
--- a/resources/src/mediawiki.api/parse.js
+++ b/resources/src/mediawiki.api/parse.js
@@ -11,15 +11,15 @@
 		 * @return {jQuery.Promise<string>} Promise that resolves with the parsed HTML of `wikitext`
 		 */
 		parse: function ( content, additionalParams ) {
-			let apiPromise,
-				config = Object.assign( {
-					formatversion: 2,
-					action: 'parse',
-					// Minimize the JSON we get back, there is no way to access anything else anyway
-					prop: 'text',
-					contentmodel: 'wikitext'
-				}, additionalParams );
+			const config = Object.assign( {
+				formatversion: 2,
+				action: 'parse',
+				// Minimize the JSON we get back, there is no way to access anything else anyway
+				prop: 'text',
+				contentmodel: 'wikitext'
+			}, additionalParams );
 
+			let apiPromise;
 			if ( mw.Title && content instanceof mw.Title ) {
 				// Parse existing page
 				config.page = content.getPrefixedDb();
diff --git a/resources/src/mediawiki.api/rest.js b/resources/src/mediawiki.api/rest.js
index 5335c50d3492..2dce3a5854ba 100644
--- a/resources/src/mediawiki.api/rest.js
+++ b/resources/src/mediawiki.api/rest.js
@@ -177,18 +177,17 @@
 		 *  Fail: Error code
 		 */
 		ajax: function ( path, ajaxOptions ) {
-			let self = this,
-				apiDeferred = $.Deferred(),
-				xhr, requestIndex;
+			const self = this,
+				apiDeferred = $.Deferred();
 
 			ajaxOptions = Object.assign( {}, this.defaults.ajax, ajaxOptions );
 			ajaxOptions.url = this.url + path;
 
 			// Make the AJAX request.
-			xhr = $.ajax( ajaxOptions );
+			const xhr = $.ajax( ajaxOptions );
 
 			// Save it to make it possible to abort.
-			requestIndex = this.requests.length;
+			const requestIndex = this.requests.length;
 			this.requests.push( xhr );
 			xhr.always( () => {
 				self.requests[ requestIndex ] = null;
diff --git a/resources/src/mediawiki.api/upload.js b/resources/src/mediawiki.api/upload.js
index f061fb25a89b..4f7d096b820d 100644
--- a/resources/src/mediawiki.api/upload.js
+++ b/resources/src/mediawiki.api/upload.js
@@ -62,10 +62,9 @@
 		 * @return {jQuery.Promise}
 		 */
 		uploadWithFormData: function ( file, data ) {
-			let key, request,
-				deferred = $.Deferred();
+			const deferred = $.Deferred();
 
-			for ( key in data ) {
+			for ( const key in data ) {
 				if ( !fieldsAllowed[ key ] ) {
 					delete data[ key ];
 				}
@@ -81,7 +80,7 @@
 			}
 
 			// Use this.postWithEditToken() or this.post()
-			request = this[ this.needToken() ? 'postWithEditToken' : 'post' ]( data, {
+			const request = this[ this.needToken() ? 'postWithEditToken' : 'post' ]( data, {
 				// Use FormData (if we got here, we know that it's available)
 				contentType: 'multipart/form-data',
 				// No timeout (default from mw.Api is 30 seconds)
@@ -127,8 +126,7 @@
 		 * @return {jQuery.Promise}
 		 */
 		chunkedUpload: function ( file, data, chunkSize, chunkRetries ) {
-			let start, end, promise, next, active,
-				deferred = $.Deferred();
+			const deferred = $.Deferred();
 
 			chunkSize = chunkSize === undefined ? 5 * 1024 * 1024 : chunkSize;
 			chunkRetries = chunkRetries === undefined ? 1 : chunkRetries;
@@ -137,16 +135,17 @@
 				throw new Error( 'Filename not included in file data.' );
 			}
 
+			let promise;
 			// Submit first chunk to get the filekey
-			active = promise = this.uploadChunk( file, data, 0, chunkSize, '', chunkRetries )
+			let active = promise = this.uploadChunk( file, data, 0, chunkSize, '', chunkRetries )
 				.done( chunkSize >= file.size ? deferred.resolve : null )
 				.fail( deferred.reject )
 				.progress( deferred.notify );
 
 			// Now iteratively submit the rest of the chunks
-			for ( start = chunkSize; start < file.size; start += chunkSize ) {
-				end = Math.min( start + chunkSize, file.size );
-				next = $.Deferred();
+			for ( let start = chunkSize; start < file.size; start += chunkSize ) {
+				const end = Math.min( start + chunkSize, file.size );
+				const next = $.Deferred();
 
 				// We could simply chain one this.uploadChunk after another with
 				// .then(), but then we'd hit an `Uncaught RangeError: Maximum
@@ -183,8 +182,7 @@
 		 * @return {jQuery.Promise}
 		 */
 		uploadChunk: function ( file, data, start, end, filekey, retries ) {
-			let upload,
-				api = this,
+			const api = this,
 				chunk = this.slice( file, start, end );
 
 			// When uploading in chunks, we're going to be issuing a lot more
@@ -203,12 +201,10 @@
 				data.filekey = filekey;
 			}
 
-			upload = this.uploadWithFormData( file, data );
+			const upload = this.uploadWithFormData( file, data );
 			return upload.then(
 				null,
 				( code, result ) => {
-					let retry;
-
 					// uploadWithFormData will reject uploads with warnings, but
 					// these warnings could be "harmless" or recovered from
 					// (e.g. exists-normalized, when it'll be renamed later)
@@ -233,7 +229,7 @@
 					}
 
 					// If the call flat out failed, we may want to try again...
-					retry = api.uploadChunk.bind( api, file, data, start, end, filekey, retries - 1 );
+					const retry = api.uploadChunk.bind( api, file, data, start, end, filekey, retries - 1 );
 					return api.retry( code, result, retry );
 				},
 				// Since we're only uploading small parts of a file, we
@@ -253,9 +249,8 @@
 		 * @return {jQuery.Promise}
 		 */
 		retry: function ( code, result, callable ) {
-			let uploadPromise,
-				retryTimer,
-				deferred = $.Deferred(),
+			let uploadPromise;
+			const deferred = $.Deferred(),
 				// Wrap around the callable, so that once it completes, it'll
 				// resolve/reject the promise we'll return
 				retry = function () {
@@ -269,7 +264,7 @@
 				return deferred.reject( code, result );
 			}
 
-			retryTimer = setTimeout( retry, 1000 );
+			const retryTimer = setTimeout( retry, 1000 );
 			return deferred.promise( { abort: function () {
 				// Clear the scheduled upload, or abort if already in flight
 				if ( retryTimer ) {
@@ -325,8 +320,8 @@
 		 *  function that should be called to finish the upload.
 		 */
 		finishUploadToStash: function ( uploadPromise, data ) {
-			let filekey,
-				api = this;
+			const api = this;
+			let filekey;
 
 			function finishUpload( moreData ) {
 				return api.uploadFromStash( filekey, Object.assign( {}, data, moreData ) );
@@ -375,13 +370,11 @@
 		 *  function that should be called to finish the upload.
 		 */
 		uploadToStash: function ( file, data ) {
-			let promise;
-
 			if ( !data.filename ) {
 				throw new Error( 'Filename not included in file data.' );
 			}
 
-			promise = this.upload( file, { stash: true, filename: data.filename, ignorewarnings: data.ignorewarnings } );
+			const promise = this.upload( file, { stash: true, filename: data.filename, ignorewarnings: data.ignorewarnings } );
 
 			return this.finishUploadToStash( promise, data );
 		},
@@ -401,13 +394,11 @@
 		 *  function that should be called to finish the upload.
 		 */
 		chunkedUploadToStash: function ( file, data, chunkSize, chunkRetries ) {
-			let promise;
-
 			if ( !data.filename ) {
 				throw new Error( 'Filename not included in file data.' );
 			}
 
-			promise = this.chunkedUpload(
+			const promise = this.chunkedUpload(
 				file,
 				{ stash: true, filename: data.filename, ignorewarnings: data.ignorewarnings },
 				chunkSize,