splitChunks.maxAsyncRequests
Type: number
Default: 30
Maximum number of parallel requests when on-demand loading.
splitChunks.maxInitialRequests
Type: number
Default: 30
Maximum number of parallel requests at an entry point.
splitChunks.minChunks
splitChunks.cacheGroups.{cacheGroup}.minChunks
Type: number
Default: 1
The minimum times must a module be shared among chunks before splitting.
splitChunks.hidePathInfo
Type: boolean
Default: defaults to true if options.mode is 'production', otherwise defaults to false
Prevents exposing path info when creating names for parts splitted by maxSize.
splitChunks.minSize
Type: number
Default: 20000 in production and 10000 in others
Minimum size, in bytes, for a chunk to be generated.
splitChunks.maxSize
number = 0
Using maxSize (either globally optimization.splitChunks.maxSize per cache group optimization.splitChunks.cacheGroups[x].maxSize or for the fallback cache group optimization.splitChunks.fallbackCacheGroup.maxSize) tells Rspack to try to split chunks bigger than maxSize bytes into smaller parts. Parts will be at least minSize (next to maxSize) in size.
The algorithm is deterministic and changes to the modules will only have local effects. So that it is usable when using long term caching and doesn't require records. maxSize is only a hint and could be violated when modules are bigger than maxSize or splitting would violate minSize.
When the chunk has a name already, each part will get a new name derived from that name. Depending on the value of optimization.splitChunks.hidePathInfo it will add a key derived from the first module name or a hash of it.
maxSize option is intended to be used with HTTP/2 and long term caching. It increases the request count for better caching. It could also be used to decrease the file size for faster rebuilding.
maxSize takes higher priority than maxInitialRequest/maxAsyncRequests. Actual priority is maxInitialRequest/maxAsyncRequests < maxSize < minSize.
Setting the value for maxSize sets the value for both maxAsyncSize and maxInitialSize.
splitChunks.maxAsyncSize
number
Like maxSize, maxAsyncSize can be applied globally (splitChunks.maxAsyncSize), to cacheGroups (splitChunks.cacheGroups.{cacheGroup}.maxAsyncSize), or to the fallback cache group (splitChunks.fallbackCacheGroup.maxAsyncSize).
The difference between maxAsyncSize and maxSize is that maxAsyncSize will only affect on-demand loading chunks.
splitChunks.maxInitialSize
number
Like maxSize, maxInitialSize can be applied globally (splitChunks.maxInitialSize), to cacheGroups (splitChunks.cacheGroups.{cacheGroup}.maxInitialSize), or to the fallback cache group (splitChunks.fallbackCacheGroup.maxInitialSize).
The difference between maxInitialSize and maxSize is that maxInitialSize will only affect initial load chunks.
splitChunks.automaticNameDelimiter
Type: string
Default: -
By default Rspack will generate names using origin and name of the chunk (e.g. vendors-main.js).
This option lets you specify the delimiter to use for the generated names.
splitChunks.name
splitChunks.cacheGroups.{cacheGroup}.name
Type: string | function
Default: false
where the version of the function type is >=0.4.1.
Also available for each cacheGroup: splitChunks.cacheGroups.{cacheGroup}.name.
The name of the split chunk. Providing false will keep the same name of the chunks so it doesn't change names unnecessarily. It is the recommended value for production builds.
Providing a string allows you to use a custom name. Specifying a string will merge all common modules and vendors into a single chunk. This might lead to bigger initial downloads and slow down page loads.
If the splitChunks.name matches an entry point name, the entry point will be removed.
splitChunks.cacheGroups.{cacheGroup}.name can be used to move modules into a chunk that is a parent of the source chunk. For example, use name: "entry-name" to move modules into the entry-name chunk. You can also use on demand named chunks, but you must be careful that the selected modules are only used under this chunk.
splitChunks.cacheGroups
Cache groups can inherit and/or override any options from splitChunks.*; but test, priority and reuseExistingChunk can only be configured on cache group level. To disable any of the default cache groups, set them to false.
rspack.config.js
module.exports = {
//...
optimization: {
splitChunks: {
cacheGroups: {
default: false,
splitChunks.cacheGroups.{cacheGroup}.priority
Type: number
Default: -20
A module can belong to multiple cache groups. The optimization will prefer the cache group with a higher priority. The default groups have a negative priority to allow custom groups to take higher priority (default value is 0 for custom groups).
splitChunks.cacheGroups.{cacheGroup}.test
Type: RegExp | string | function
where the version of the function type is >=0.4.1.
Controls which modules are selected by this cache group. Omitting it selects all modules. It can match the absolute module resource path or chunk names. When a chunk name is matched, all modules in the chunk are selected.
splitChunks.cacheGroups.{cacheGroup}.enforce
Type: boolean
Tells Rspack to ignore splitChunks.minSize, splitChunks.minChunks, splitChunks.maxAsyncRequests and splitChunks.maxInitialRequests options and always create chunks for this cache group.
splitChunks.cacheGroups.{cacheGroup}.idHint
Type: string
Sets the hint for chunk id. It will be added to chunk's filename.
splitChunks.cacheGroups.{cacheGroup}.filename
Type: string
Allows to override the filename when and only when it's an initial chunk. All placeholders available in output.filename are also available here.
rspack.config.js
module.exports = {
//...
optimization: {
splitChunks: {
cacheGroups: {
defaultVendors: {
