Which reporters ship with Newman's `-r` option, and how does it resolve a name that is not built in?

## What `-r` actually selects `-r, --reporters` takes a comma-separated list — no spaces around the commas — and the option's default value is `['cli']`. The value is produced by splitting the supplied string, so passing the option **replaces** the default rather than adding to it. Each name in the resulting list is turned into a reporter *constructor*, which Newman then instantiates as `new Reporter(emitter, reporterOptions, options)`. A reporter is therefore just an object that subscribes to the run's events; nothing about a reporter changes what is sent or what passes. ## The five that ship in the box | Name | What it produces | Default file when no export path is given | |---|---|---| | `cli` | the running assertion log and the summary tables in the terminal | none — it writes to the terminal | | `json` | the run summary serialised as JSON | `newman-run-report.json` | | `junit` | an XML report built from the run's executions | `newman-run-report.xml` | | `progress` | a single progress bar advancing once per item | none — it writes to the terminal | | `emojitrain` | one emoji per item, happy or sad | none — it writes to the terminal | That list is exhaustive: those five are the only reporters present in Newman's own source. Everything else is a separate package. ## How a name becomes a module For each name in the list, in order: 1. Newman builds a package name by the **`newman-reporter-<name>` convention** and `require`s it. A scoped name is handled by moving the scope to the front: `@acme/teamcity` is loaded as `@acme/newman-reporter-teamcity`. 2. If that `require` throws, Newman falls back to the bundled map and uses the built-in of that name, if one exists. 3. If neither resolves, it warns — `newman: could not find "<name>" reporter`, plus a reminder that the reporter must be installed in the same directory as Newman — and moves on. 4. If a reporter is found but its constructor throws, Newman warns `could not load "<name>" reporter`, prints the error, and still continues. Two consequences follow, and both surprise people: - **The external lookup happens first.** Installing a package literally named `newman-reporter-cli` beside Newman would shadow the built-in `cli`. Resolution is external-first, built-in-second. - **A missing or broken reporter never fails the run.** The requests still go out, the assertions still run, and the exit code is decided by the run's failures — not by whether your report was produced. A pipeline that depends on a report file must check for the file itself. ## Options for one reporter or for all of them Reporter settings are passed as prefixed options, which Newman strips out of the argument vector before `commander` parses it, then re-parses on its own: - `--reporter-<name>-<option>` targets one reporter: `--reporter-cli-no-banner`, `--reporter-junit-export ./reports/junit.xml`. - `--reporter-<option>` with no reporter name is generic and is merged into **every** reporter's options: `--reporter-silent` quiets all of them at once. - A prefixed option with no value becomes boolean `true`; the rest of the name is camel-cased, so `--reporter-cli-no-summary` reaches the `cli` reporter as `noSummary`. ## Dominant reporters Three of the built-ins mark themselves **dominant**: `cli`, `progress` and `emojitrain`. All three write to the terminal, and two of them would fight over the same lines. When more than one dominant reporter ends up in the list, Newman warns `<a>, <b> reporters might not work well together` — a warning, again, not an error. `json` and `junit` write files and are not dominant, which is why pairing one of them with `cli` is the ordinary combination. ## The name that is documented but not shipped `newman-reporter-htmlextra` shows up in Newman's own documentation, and many teams assume it is bundled. It is not present anywhere in Newman's source. The same is true of `newman-reporter-html` and `newman-reporter-teamcity`, both of which Newman knows well enough to print an install hint for when the name is missing — that hint is exactly the evidence that they live outside the package. Assert the five built-ins and describe everything else as an external package resolved by the naming convention. ## Checklist for a real command - Name `cli` explicitly whenever you add another reporter, or you lose the terminal output. - Give any file-writing reporter an export path, or the file lands somewhere you did not choose. - Do not pair two dominant reporters unless you enjoy interleaved output. - Verify the report file exists after the run; a warning about a missing reporter will not stop the pipeline for you.