docs: add documentation for --outputTruncateLength cli flag

docs/config/index.md

@@ -237,6 +237,14 @@ Custom reporters for output. Reporters can be [a Reporter instance](https://gith
   - `'json'` -  give a simple JSON summary
   - path of a custom reporter (e.g. `'./path/to/reporter.ts'`, `'@scope/reporter'`)
 
+### outputTruncateLength
+
+- **Type:** `number`
+- **Default:** `80`
+
+Truncate output diff lines up to `80` number of characters. You may wish to tune this,
+depending on you terminal window width.
+
 ### outputFile
 
 - **Type:** `string | Record<string, string>`

docs/guide/cli.md

@@ -54,6 +54,7 @@ vitest related /src/index.ts /src/hello-world.js
 | `--silent` | Silent console output from tests |
 | `--isolate` | Isolate environment for each test file (default: `true`) |
 | `--reporter <name>` | Select reporter: `default`, `verbose`, `dot`, `junit`, `json`, or a path to a custom reporter |
+| `--outputTruncateLength <length>` | Truncate output diff lines up to `<length>` number of characters. |
 | `--outputFile <filename/-s>` | Write test results to a file when the `--reporter=json` or `--reporter=junit` option is also specified <br /> Via [cac's dot notation] you can specify individual outputs for multiple reporters |
 | `--coverage` | Use c8 for coverage |
 | `--run` | Do not watch |

packages/vitest/src/node/cli.ts

@@ -22,7 +22,7 @@ cli
   .option('--silent', 'silent console output from tests')
   .option('--isolate', 'isolate environment for each test file (default: true)')
   .option('--reporter <name>', 'reporter')
-  .option('--outputTruncateLength <length>', 'diff output length')
+  .option('--outputTruncateLength <length>', 'diff output length (default: 80)')
   .option('--outputFile <filename/-s>', 'write test results to a file when the --reporter=json or --reporter=junit option is also specified, use cac\'s dot notation for individual outputs of mutliple reporters')
   .option('--coverage', 'use c8 for coverage')
   .option('--run', 'do not watch')