lib.id#

• Type: string
• Default: undefined

Specify the library ID. The ID identifies the library and is useful when using the --lib flag to build specific libraries with a meaningful id in the CLI.

Default Value#

By default, Rslib automatically generates an ID for each library in the format ${format}${index}. Here, format refers to the value specified in the current lib's format, and index indicates the order of the library within all libraries of the same format. If there is only one library with the current format, the index will be empty. Otherwise, it will start from 0 and increment.

For example, the libraries in the esm format will start from esm0, followed by esm1, esm2, and so on. In contrast, cjs and umd formats do not include the index part since there is only one library for each format.

export default {
  lib: [
    { format: 'esm' }, // id is `esm0`
    { format: 'cjs' }, // id is `cjs`
    { format: 'esm' }, // id is `esm1`
    { format: 'umd' }, // id is `umd`
    { format: 'esm' }, // id is `esm2`
  ],
};

Customize ID#

You can also specify a readable or meaningful ID of the library by setting the id field in the library configuration. The user-specified ID will take priority, while the rest will be used together to generate the default ID.

For example, my-lib-a, my-lib-b, and my-lib-c will be the IDs of the specified libraries, while the rest will be used to generate and apply the default ID.

export default {
  lib: [
    { format: 'esm', id: 'my-lib-a' }, // ID is `my-lib-a`
    { format: 'cjs', id: 'my-lib-b' }, // ID is `my-lib-b`
    { format: 'esm' },                 // ID is `esm0`
    { format: 'umd', id: 'my-lib-c' }, // ID is `my-lib-c`
    { format: 'esm' },                 // ID is `esm1`
  ],
};

Then you could only build my-lib-a and my-lib-b by running the following command:

npx rslib build --lib my-lib-a --lib my-lib-b