The input was not validated so far and that caused unwanted side
effects. E.g., `undefined` became the string `'undefined'`. It was
expected to fail or to end up as empty string.
Now all input is validated to be either some type of array buffer
view or a string. That way it's always clear what the user intents.
PR-URL: #31030
Fixes: #31025
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

PR-URL: #31030
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

PR-URL: #31731
Refs: #31030
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>

- Use Node.js 14 in actions/setup-node
- Add Node.js 14.x to the test matrix
- Remove CI: true from the environment
The variable is already set by GitHub
- Fix bug in test fixture
Discovered with v14.x because of
nodejs/node#31030.

- Use Node.js 14 in actions/setup-node
- Add Node.js 14.x to the test matrix
- Remove CI: true from the environment
The variable is already set by GitHub
- Fix bug in test fixture
Discovered with v14.x because of
nodejs/node#31030.

A Node.js 14.x added strict type checking when writing files to disk,
preventing methods with their own `.toString()` method from being
written to disk and generating a `ERR_INVALID_ARG_TYPE` error in the
process. This affected using this plugin in combination with
`--source-map`.
The behavioral change was introduced in
nodejs/node#31030 and recently fixed in
nodejs/node#34993. That fix was not
comprehensive, and did not resolve the issue for the plugin.
To avoid this issue for all versions of Node, we no longer assume there
will be an implicit call to `SourceMapGenerator.toString()`. Instead,
it's now explicitly called when setting the data to write for the source
map, fixing source map generation.
This was tested on the latest releases of Node 12 through 15.