diff --git a/lib/AsyncDependenciesBlock.js b/lib/AsyncDependenciesBlock.js
index f3112bbf5..c52457b55 100644
--- a/lib/AsyncDependenciesBlock.js
+++ b/lib/AsyncDependenciesBlock.js
@@ -86,9 +86,11 @@ module.exports = class AsyncDependenciesBlock extends DependenciesBlock {
 	}
 
 	/**
+	 * Sorts items in this module
+	 * @param {boolean=} sortChunks sort the chunks too
 	 * @returns {void}
 	 */
-	sortItems() {
+	sortItems(sortChunks) {
 		super.sortItems();
 	}
 };
diff --git a/lib/ContextModule.js b/lib/ContextModule.js
index 9f890684a..2912c3824 100644
--- a/lib/ContextModule.js
+++ b/lib/ContextModule.js
@@ -205,6 +205,11 @@ class ContextModule extends Module {
 		return identifier;
 	}
 
+	/**
+	 * @param {TODO} fileTimestamps timestamps of files
+	 * @param {TODO} contextTimestamps timestamps of directories
+	 * @returns {boolean} true, if the module needs a rebuild
+	 */
 	needRebuild(fileTimestamps, contextTimestamps) {
 		const ts = contextTimestamps.get(this.context);
 		if (!ts) {
diff --git a/lib/DelegatedModule.js b/lib/DelegatedModule.js
index 6ecdbf7e6..19f5ca756 100644
--- a/lib/DelegatedModule.js
+++ b/lib/DelegatedModule.js
@@ -58,7 +58,12 @@ class DelegatedModule extends Module {
 		return `delegated ${this.userRequest} from ${this.sourceRequest}`;
 	}
 
-	needRebuild() {
+	/**
+	 * @param {TODO} fileTimestamps timestamps of files
+	 * @param {TODO} contextTimestamps timestamps of directories
+	 * @returns {boolean} true, if the module needs a rebuild
+	 */
+	needRebuild(fileTimestamps, contextTimestamps) {
 		return false;
 	}
 
diff --git a/lib/DependenciesBlock.js b/lib/DependenciesBlock.js
index 142f3eacb..a7dfa6555 100644
--- a/lib/DependenciesBlock.js
+++ b/lib/DependenciesBlock.js
@@ -116,7 +116,12 @@ class DependenciesBlock {
 		return false;
 	}
 
-	sortItems() {
+	/**
+	 * Sorts items in this module
+	 * @param {boolean=} sortChunks sort the chunks too
+	 * @returns {void}
+	 */
+	sortItems(sortChunks) {
 		for (const block of this.blocks) block.sortItems();
 	}
 }
diff --git a/lib/DllModule.js b/lib/DllModule.js
index 50a8c5b8b..983467ee7 100644
--- a/lib/DllModule.js
+++ b/lib/DllModule.js
@@ -64,7 +64,12 @@ class DllModule extends Module {
 		return new RawSource("module.exports = __webpack_require__;");
 	}
 
-	needRebuild() {
+	/**
+	 * @param {TODO} fileTimestamps timestamps of files
+	 * @param {TODO} contextTimestamps timestamps of directories
+	 * @returns {boolean} true, if the module needs a rebuild
+	 */
+	needRebuild(fileTimestamps, contextTimestamps) {
 		return false;
 	}
 
diff --git a/lib/ExternalModule.js b/lib/ExternalModule.js
index 772c3c7c2..89d6aada5 100644
--- a/lib/ExternalModule.js
+++ b/lib/ExternalModule.js
@@ -55,7 +55,12 @@ class ExternalModule extends Module {
 		return "external " + JSON.stringify(this.request);
 	}
 
-	needRebuild() {
+	/**
+	 * @param {TODO} fileTimestamps timestamps of files
+	 * @param {TODO} contextTimestamps timestamps of directories
+	 * @returns {boolean} true, if the module needs a rebuild
+	 */
+	needRebuild(fileTimestamps, contextTimestamps) {
 		return false;
 	}
 
diff --git a/lib/Module.js b/lib/Module.js
index 1d4885468..13b11b255 100644
--- a/lib/Module.js
+++ b/lib/Module.js
@@ -10,7 +10,9 @@ const SortableSet = require("./util/SortableSet");
 const Template = require("./Template");
 
 /** @typedef {import("./Chunk")} Chunk */
+/** @typedef {import("./ChunkGroup")} ChunkGroup */
 /** @typedef {import("./Compilation")} Compilation */
+/** @typedef {import("./Dependency")} Dependency */
 /** @typedef {import("./RequestShortener")} RequestShortener */
 /** @typedef {import("./DependencyTemplates")} DependencyTemplates */
 /** @typedef {import("./RuntimeTemplate")} RuntimeTemplate */
@@ -118,6 +120,10 @@ class Module extends DependenciesBlock {
 		return (this.buildInfo && this.buildInfo.moduleArgument) || "module";
 	}
 
+	/**
+	 * disconnect the module from the graph
+	 * @returns {void}
+	 */
 	disconnect() {
 		this.hash = undefined;
 		this.renderedHash = undefined;
@@ -140,6 +146,9 @@ class Module extends DependenciesBlock {
 		super.disconnect();
 	}
 
+	/**
+	 * @returns {void}
+	 */
 	unseal() {
 		this.id = null;
 		this.index = null;
@@ -149,16 +158,30 @@ class Module extends DependenciesBlock {
 		super.unseal();
 	}
 
+	/**
+	 * Sets the chunks to a new value
+	 * @protected
+	 * @param {Iterable<Chunk>} chunks the new chunks
+	 * @returns {void}
+	 */
 	setChunks(chunks) {
 		this._chunks = new SortableSet(chunks, sortById);
 	}
 
+	/**
+	 * @param {Chunk} chunk added chunk
+	 * @returns {boolean} true, if the chunk could be added
+	 */
 	addChunk(chunk) {
 		if (this._chunks.has(chunk)) return false;
 		this._chunks.add(chunk);
 		return true;
 	}
 
+	/**
+	 * @param {Chunk} chunk removed chunk
+	 * @returns {boolean} true, if the chunk could be removed
+	 */
 	removeChunk(chunk) {
 		if (this._chunks.delete(chunk)) {
 			chunk.removeModule(this);
@@ -167,10 +190,17 @@ class Module extends DependenciesBlock {
 		return false;
 	}
 
+	/**
+	 * @param {Chunk} chunk chunk to be tested
+	 * @returns {boolean} true, if the module is in a chunk
+	 */
 	isInChunk(chunk) {
 		return this._chunks.has(chunk);
 	}
 
+	/**
+	 * @returns {boolean} true, if the module is entry of any chunk
+	 */
 	isEntryModule() {
 		for (const chunk of this._chunks) {
 			if (chunk.entryModule === this) return true;
@@ -178,6 +208,9 @@ class Module extends DependenciesBlock {
 		return false;
 	}
 
+	/**
+	 * @returns {boolean} true, if the module is optional
+	 */
 	get optional() {
 		return (
 			this.reasons.length > 0 &&
@@ -192,14 +225,24 @@ class Module extends DependenciesBlock {
 		return Array.from(this._chunks);
 	}
 
+	/**
+	 * @returns {number} the number of chunk which contain the module
+	 */
 	getNumberOfChunks() {
 		return this._chunks.size;
 	}
 
+	/**
+	 * @returns {Iterable<Chunk>} chunks that contain the module
+	 */
 	get chunksIterable() {
 		return this._chunks;
 	}
 
+	/**
+	 * @param {Module} otherModule some other module
+	 * @returns {boolean} true, if modules are in the same chunks
+	 */
 	hasEqualsChunks(otherModule) {
 		if (this._chunks.size !== otherModule._chunks.size) return false;
 		this._chunks.sortWith(sortByDebugId);
@@ -215,10 +258,21 @@ class Module extends DependenciesBlock {
 		}
 	}
 
+	/**
+	 * @param {Module=} module referenced module
+	 * @param {Dependency=} dependency referencing dependency
+	 * @param {string=} explanation some explanation
+	 * @returns {void}
+	 */
 	addReason(module, dependency, explanation) {
 		this.reasons.push(new ModuleReason(module, dependency, explanation));
 	}
 
+	/**
+	 * @param {Module=} module referenced module
+	 * @param {Dependency=} dependency referencing dependency
+	 * @returns {boolean} true, if the reason could be removed
+	 */
 	removeReason(module, dependency) {
 		for (let i = 0; i < this.reasons.length; i++) {
 			let r = this.reasons[i];
@@ -230,6 +284,11 @@ class Module extends DependenciesBlock {
 		return false;
 	}
 
+	/**
+	 * @param {Chunk} chunk a chunk
+	 * @param {Chunk=} ignoreChunk chunk to be ignored
+	 * @returns {boolean} true, if the module is accessible from "chunk" when ignoring "ignoreChunk"
+	 */
 	isAccessibleInChunk(chunk, ignoreChunk) {
 		// Check if module is accessible in ALL chunk groups
 		for (const chunkGroup of chunk.groupsIterable) {
@@ -238,6 +297,11 @@ class Module extends DependenciesBlock {
 		return true;
 	}
 
+	/**
+	 * @param {ChunkGroup} chunkGroup a chunk group
+	 * @param {Chunk=} ignoreChunk chunk to be ignored
+	 * @returns {boolean} true, if the module is accessible from "chunkGroup" when ignoring "ignoreChunk"
+	 */
 	isAccessibleInChunkGroup(chunkGroup, ignoreChunk) {
 		const queue = new Set([chunkGroup]);
 
@@ -258,6 +322,10 @@ class Module extends DependenciesBlock {
 		return true;
 	}
 
+	/**
+	 * @param {Chunk} chunk a chunk
+	 * @returns {boolean} true, if the module has any reason why "chunk" should be included
+	 */
 	hasReasonForChunk(chunk) {
 		// check for each reason if we need the chunk
 		for (const reason of this.reasons) {
@@ -270,10 +338,19 @@ class Module extends DependenciesBlock {
 		return false;
 	}
 
+	/**
+	 * @returns {boolean} true, if there are references to this module
+	 */
 	hasReasons() {
 		return this.reasons.length > 0;
 	}
 
+	/**
+	 * @param {string=} exportName a name of an export
+	 * @returns {string | boolean} true, when no "exportName" is provided and the module is used.
+	 *                             false, when module or referenced export is unused.
+	 *                             string, the mangled export name when used.
+	 */
 	isUsed(exportName) {
 		if (!exportName) return this.used !== false;
 		if (this.used === null || this.usedExports === null) return exportName;
@@ -298,15 +375,29 @@ class Module extends DependenciesBlock {
 		return exportName;
 	}
 
+	/**
+	 * @param {string} exportName a name of an export
+	 * @returns {boolean | null} true, if the export is provided why the module.
+	 *                           null, if it's unknown.
+	 *                           false, if it's not provided.
+	 */
 	isProvided(exportName) {
 		if (!Array.isArray(this.buildMeta.providedExports)) return null;
 		return this.buildMeta.providedExports.includes(exportName);
 	}
 
+	/**
+	 * @returns {string} for debugging
+	 */
 	toString() {
 		return `Module[${this.id || this.debugId}]`;
 	}
 
+	/**
+	 * @param {TODO} fileTimestamps timestamps of files
+	 * @param {TODO} contextTimestamps timestamps of directories
+	 * @returns {boolean} true, if the module needs a rebuild
+	 */
 	needRebuild(fileTimestamps, contextTimestamps) {
 		return true;
 	}
@@ -321,6 +412,11 @@ class Module extends DependenciesBlock {
 		super.updateHash(hash);
 	}
 
+	/**
+	 * Sorts items in this module
+	 * @param {boolean=} sortChunks sort the chunks too
+	 * @returns {void}
+	 */
 	sortItems(sortChunks) {
 		super.sortItems();
 		if (sortChunks) this._chunks.sort();
@@ -335,6 +431,9 @@ class Module extends DependenciesBlock {
 		}
 	}
 
+	/**
+	 * @returns {void}
+	 */
 	unbuild() {
 		this.dependencies.length = 0;
 		this.blocks.length = 0;
diff --git a/lib/MultiModule.js b/lib/MultiModule.js
index d89e52989..15ecdecc1 100644
--- a/lib/MultiModule.js
+++ b/lib/MultiModule.js
@@ -59,7 +59,12 @@ class MultiModule extends Module {
 		return callback();
 	}
 
-	needRebuild() {
+	/**
+	 * @param {TODO} fileTimestamps timestamps of files
+	 * @param {TODO} contextTimestamps timestamps of directories
+	 * @returns {boolean} true, if the module needs a rebuild
+	 */
+	needRebuild(fileTimestamps, contextTimestamps) {
 		return false;
 	}
 
diff --git a/lib/NormalModule.js b/lib/NormalModule.js
index e9191b0ed..ba818c8d9 100644
--- a/lib/NormalModule.js
+++ b/lib/NormalModule.js
@@ -536,6 +536,11 @@ class NormalModule extends Module {
 		return this._source;
 	}
 
+	/**
+	 * @param {TODO} fileTimestamps timestamps of files
+	 * @param {TODO} contextTimestamps timestamps of directories
+	 * @returns {boolean} true, if the module needs a rebuild
+	 */
 	needRebuild(fileTimestamps, contextTimestamps) {
 		// always try to rebuild in case of an error
 		if (this.error) return true;
diff --git a/lib/RawModule.js b/lib/RawModule.js
index 15aba1691..42313a9c3 100644
--- a/lib/RawModule.js
+++ b/lib/RawModule.js
@@ -45,7 +45,12 @@ module.exports = class RawModule extends Module {
 		return requestShortener.shorten(this.readableIdentifierStr);
 	}
 
-	needRebuild() {
+	/**
+	 * @param {TODO} fileTimestamps timestamps of files
+	 * @param {TODO} contextTimestamps timestamps of directories
+	 * @returns {boolean} true, if the module needs a rebuild
+	 */
+	needRebuild(fileTimestamps, contextTimestamps) {
 		return false;
 	}