webpack/webpack · error · Error

Unsupported chunk format '${options.output.chunkFormat}'.

Error message

Unsupported chunk format '${options.output.chunkFormat}'.

What it means

Error "Unsupported chunk format '${options.output.chunkFormat}'." thrown in webpack/webpack.

Source

Thrown at lib/WebpackOptionsApply.js:352

					const ArrayPushCallbackChunkFormatPlugin = require("./javascript/ArrayPushCallbackChunkFormatPlugin");

					new ArrayPushCallbackChunkFormatPlugin().apply(compiler);
					break;
				}
				case "commonjs": {
					const CommonJsChunkFormatPlugin = require("./javascript/CommonJsChunkFormatPlugin");

					new CommonJsChunkFormatPlugin().apply(compiler);
					break;
				}
				case "module": {
					const ModuleChunkFormatPlugin = require("./esm/ModuleChunkFormatPlugin");

					new ModuleChunkFormatPlugin().apply(compiler);
					break;
				}
				default:
					throw new Error(
						`Unsupported chunk format '${options.output.chunkFormat}'.`
					);
			}
		}

		const enabledChunkLoadingTypes =
			/** @type {NonNullable<WebpackOptions["output"]["enabledChunkLoadingTypes"]>} */
			(options.output.enabledChunkLoadingTypes);

		if (enabledChunkLoadingTypes.length > 0) {
			for (const type of enabledChunkLoadingTypes) {
				const EnableChunkLoadingPlugin = require("./javascript/EnableChunkLoadingPlugin");

				new EnableChunkLoadingPlugin(type).apply(compiler);
			}
		}

		const enabledWasmLoadingTypes =

View on GitHub (pinned to 318421ea8a)

Solutions

1. Set output.chunkFormat to a supported value for the selected target (e.g. 'array-push', 'commonjs', or 'module'), or leave it unset to use the default.

When it happens

Trigger: Thrown at lib/WebpackOptionsApply.js:352 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of webpack/webpack@318421ea8a (2026-08-03). Data as JSON: /data/errors/22afd7b891f8c194.json. Report an issue: GitHub.