module: custom --conditions flag option

PR-URL: https://github.com/nodejs/node/pull/34637
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Geoffrey Booth <webmaster@geoffreybooth.com>
Reviewed-By: Jan Krems <jan.krems@gmail.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/doc/api/esm.md b/doc/api/esm.md
index 551eef604ea..adbb55f0d82 100644
--- a/doc/api/esm.md
+++ b/doc/api/esm.md
@@ -501,6 +501,21 @@ a nested conditional does not have any mapping it will continue checking
 the remaining conditions of the parent condition. In this way nested
 conditions behave analogously to nested JavaScript `if` statements.
 
+#### Resolving user conditions
+
+When running Node.js, custom user conditions can be added with the
+`--conditions` or `-u` flag:
+
+```bash
+node --conditions=development main.js
+```
+
+which would then resolve the `"development"` condition in package imports and
+exports, while resolving the existing `"node"`, `"default"`, `"import"`, and
+`"require"` conditions as appropriate.
+
+Any number of custom conditions can be set with repeat flags.
+
 #### Self-referencing a package using its name
 
 Within a package, the values defined in the package’s