fix(cli): support Jest-specific CLI flag aliases (#4124)

This adds support for the following Jest-specific CLI flag aliases:

- "b" for "bail"
- "e" for "expand"
- "w" for "maxWorkers"
- "o" for "onlyChanged"
- "f" for "onlyFailures"
- "i" for "runInBand"
- "t" for "testNamePattern"
- "u" for "updateSnapshot"

Two additional flags supported by Jest ('c' for 'config' and 'h' for
'help') were already supported by Stencil.

This also makes a small refactor to the CLI argument parser, mainly
building up the `flags.unknownArgs` array proactively whenever we're in
a situation where we don't know what to do, rather than filtering all
the arguments after the fact.

Author: alicewriteswrongs

src/cli/config-flags.ts

@@ -213,13 +213,25 @@ export const CLI_FLAG_ALIASES: AliasMap = {
   h: 'help',
   p: 'port',
   v: 'version',
+
+  // JEST SPECIFIC CLI FLAGS
+  // these are defined in
+  // https://github.com/facebook/jest/blob/4156f86/packages/jest-cli/src/args.ts
+  b: 'bail',
+  e: 'expand',
+  f: 'onlyFailures',
+  i: 'runInBand',
+  o: 'onlyChanged',
+  t: 'testNamePattern',
+  u: 'updateSnapshot',
+  w: 'maxWorkers',
 };
 
 /**
  * A regular expression which can be used to match a CLI flag for one of our
  * short aliases.
  */
-export const CLI_FLAG_REGEX = new RegExp(`^-[chpv]{1}$`);
+export const CLI_FLAG_REGEX = new RegExp(`^-[chpvbewofitu]{1}$`);
 
 /**
  * Given two types `K` and `T` where `K` extends `ReadonlyArray<string>`,

src/cli/parse-flags.ts

@@ -42,14 +42,6 @@ export const parseFlags = (args: string[]): ConfigFlags => {
     }
   }
 
-  // to find unknown / unrecognized arguments we filter `args`, including only
-  // arguments whose normalized form is not found in `knownArgs`. `knownArgs`
-  // is populated during the call to `parseArgs` above. For arguments like
-  // `--foobar` the string `"--foobar"` will be added, while for more
-  // complicated arguments like `--bizBoz=bop` or `--bizBoz bop` just the
-  // string `"--bizBoz"` will be added.
-  flags.unknownArgs = flags.args.filter((arg: string) => !flags.knownArgs.includes(parseEqualsArg(arg)[0]));
-
   return flags;
 };
 
@@ -131,13 +123,13 @@ const parseCLITerm = (flags: ConfigFlags, args: string[]) => {
   else if (arg.startsWith('-') && arg.includes('=')) {
     // we're dealing with an AliasEqualsArg, we have a special helper for that
     const [originalArg, value] = parseEqualsArg(arg);
-    setCLIArg(flags, arg.split('=')[0], normalizeFlagName(originalArg), value);
+    setCLIArg(flags, desugarRawAlias(originalArg), normalizeFlagName(originalArg), value);
   }
 
   // AliasArg → "-" AliasName ( " " CLIValue )? ;
   else if (CLI_FLAG_REGEX.test(arg)) {
     // this is a short alias, like `-c` for Config
-    setCLIArg(flags, arg, normalizeFlagName(arg), parseCLIValue(args));
+    setCLIArg(flags, desugarRawAlias(arg), normalizeFlagName(arg), parseCLIValue(args));
   }
 
   // NegativeDashArg → "--no-" ArgName ;
@@ -164,13 +156,14 @@ const parseCLITerm = (flags: ConfigFlags, args: string[]) => {
   // SimpleArg → "--" ArgName ( " " CLIValue )? ;
   else if (arg.startsWith('--') && arg.length > '--'.length) {
     setCLIArg(flags, arg, normalizeFlagName(arg), parseCLIValue(args));
+  } else {
+    // if we get here then `arg` is not an argument in our list of supported
+    // arguments. This doesn't necessarily mean we want to report an error or
+    // anything though! Instead, with unknown / unrecognized arguments we want
+    // to stick them into the `unknownArgs` array, which is used when we pass
+    // CLI args to Jest, for instance.
+    flags.unknownArgs.push(arg);
   }
-
-  // if we get here it is not an argument in our list of supported arguments.
-  // This doesn't necessarily mean we want to report an error or anything
-  // though! Instead, with unknown / unrecognized arguments we stick them into
-  // the `unknownArgs` array, which is used when we pass CLI args to Jest, for
-  // instance. So we just return void here.
 };
 
 /**
@@ -219,7 +212,7 @@ const normalizeFlagName = (flagName: string): string => {
  * @param value the raw value to be set onto the config flags object
  */
 const setCLIArg = (flags: ConfigFlags, rawArg: string, normalizedArg: string, value: CLIValueResult) => {
-  normalizedArg = dereferenceAlias(normalizedArg);
+  normalizedArg = desugarAlias(normalizedArg);
 
   // We're setting a boolean!
   if (readOnlyArrayHasStringMember(BOOLEAN_CLI_FLAGS, normalizedArg)) {
@@ -320,6 +313,14 @@ const setCLIArg = (flags: ConfigFlags, rawArg: string, normalizedArg: string, va
     } else {
       throwCLIParsingError(rawArg, 'expected to receive a valid log level but received nothing');
     }
+  } else {
+    // we haven't found this flag in any of our lists of arguments, so we
+    // should put it in our list of unknown arguments
+    flags.unknownArgs.push(rawArg);
+
+    if (typeof value === 'string') {
+      flags.unknownArgs.push(value);
+    }
   }
 };
 
@@ -355,9 +356,10 @@ type CLIValueResult = string | typeof Empty;
  * A little helper which tries to parse a CLI value (as opposed to a flag) off
  * of the argument array.
  *
- * We support a variety of different argument formats, but all of them start
- * with `-`, so we can check the first character to test whether the next token
- * in our array of CLI arguments is a flag name or a value.
+ * We support a variety of different argument formats for flags (as opposed to
+ * values), but all of them start with `-`, so we can check the first character
+ * to test whether the next token in our array of CLI arguments is a flag name
+ * or a value.
  *
  * @param args an array of CLI args
  * @returns either a string result or an Empty sentinel
@@ -454,22 +456,35 @@ const throwNumberParsingError = (flag: string, value: string) => {
 };
 
 /**
- * A little helper to 'dereference' a flag alias, which if you squint a little
- * you can think of like a pointer to a full flag name. Thus 'c' is like a
- * pointer to 'config', so here we're doing something like `*c`. Of course, this
- * being JS, this is just a metaphor!
+ * A little helper to 'desugar' a flag alias, meaning expand it to its full
+ * name. For instance, the alias `"c"` will desugar to `"config"`.
  *
- * If no 'dereference' is found for the possible alias we just return the
- * passed string unmodified.
+ * If no expansion is found for the possible alias we just return the passed
+ * string unmodified.
  *
  * @param maybeAlias a string which _could_ be an alias to a full flag name
  * @returns the full aliased flag name, if found, or the passed string if not
  */
-const dereferenceAlias = (maybeAlias: string): string => {
-  const possibleDereference = CLI_FLAG_ALIASES[maybeAlias];
+const desugarAlias = (maybeAlias: string): string => {
+  const possiblyDesugared = CLI_FLAG_ALIASES[maybeAlias];
 
-  if (typeof possibleDereference === 'string') {
-    return possibleDereference;
+  if (typeof possiblyDesugared === 'string') {
+    return possiblyDesugared;
   }
   return maybeAlias;
 };
+
+/**
+ * Desugar a 'raw' alias (with a leading dash) and return an equivalent,
+ * desugared argument.
+ *
+ * For instance, passing `"-c` will return `"--config"`.
+ *
+ * The reason we'd like to do this is not so much for our own code, but so that
+ * we can transform an alias like `"-u"` to `"--updateSnapshot"` in order to
+ * pass it along to Jest.
+ *
+ * @param rawAlias a CLI flag alias as found on the command line (like `"-c"`)
+ * @returns an equivalent full command (like `"--config"`)
+ */
+const desugarRawAlias = (rawAlias: string): string => '--' + desugarAlias(normalizeFlagName(rawAlias));

src/cli/test/parse-flags.spec.ts

@@ -3,6 +3,7 @@ import { toDashCase } from '@utils';
 import { LogLevel } from '../../declarations';
 import {
   BOOLEAN_CLI_FLAGS,
+  ConfigFlags,
   NUMBER_CLI_FLAGS,
   STRING_ARRAY_CLI_FLAGS,
   STRING_CLI_FLAGS,
@@ -230,11 +231,47 @@ describe('parseFlags', () => {
       it('should parse -c /my-config.js', () => {
         const flags = parseFlags(['-c', '/my-config.js']);
         expect(flags.config).toBe('/my-config.js');
+        expect(flags.knownArgs).toEqual(['--config', '/my-config.js']);
       });
 
       it('should parse -c=/my-config.js', () => {
         const flags = parseFlags(['-c=/my-config.js']);
         expect(flags.config).toBe('/my-config.js');
+        expect(flags.knownArgs).toEqual(['--config', '/my-config.js']);
+      });
+    });
+
+    describe('Jest aliases', () => {
+      it.each([
+        ['w', 'maxWorkers', '4'],
+        ['t', 'testNamePattern', 'testname'],
+      ])('should support the string Jest alias %p for %p', (alias, fullArgument, value) => {
+        const flags = parseFlags([`-${alias}`, value]);
+        expect(flags.knownArgs).toEqual([`--${fullArgument}`, value]);
+        expect(flags.unknownArgs).toHaveLength(0);
+      });
+
+      it.each([
+        ['w', 'maxWorkers', '4'],
+        ['t', 'testNamePattern', 'testname'],
+      ])('should support the string Jest alias %p for %p in an AliasEqualsArg', (alias, fullArgument, value) => {
+        const flags = parseFlags([`-${alias}=${value}`]);
+        expect(flags.knownArgs).toEqual([`--${fullArgument}`, value]);
+        expect(flags.unknownArgs).toHaveLength(0);
+      });
+
+      it.each<[string, keyof ConfigFlags]>([
+        ['b', 'bail'],
+        ['e', 'expand'],
+        ['o', 'onlyChanged'],
+        ['f', 'onlyFailures'],
+        ['i', 'runInBand'],
+        ['u', 'updateSnapshot'],
+      ])('should support the boolean Jest alias %p for %p', (alias, fullArgument) => {
+        const flags = parseFlags([`-${alias}`]);
+        expect(flags.knownArgs).toEqual([`--${fullArgument}`]);
+        expect(flags[fullArgument]).toBe(true);
+        expect(flags.unknownArgs).toHaveLength(0);
       });
     });
   });

src/testing/jest/test/jest-config.spec.ts

@@ -1,3 +1,4 @@
+import type { Config } from '@jest/types';
 import type * as d from '@stencil/core/declarations';
 import { mockValidatedConfig } from '@stencil/core/testing';
 import path from 'path';
@@ -225,4 +226,43 @@ describe('jest-config', () => {
     // the `_` field holds any filename pattern matches
     expect(jestArgv._).toEqual(['foobar/*', 'my-spec.ts']);
   });
+
+  describe('Jest aliases', () => {
+    it('should support the string Jest alias "-w=4" for maxWorkers', () => {
+      const args = ['test', '--spec', '-w=4'];
+      const jestArgv = buildJestArgv(mockValidatedConfig({ flags: parseFlags(args) }));
+      expect(jestArgv.maxWorkers).toBe(4);
+    });
+
+    it('should support the string Jest alias "-w 4" for maxWorkers', () => {
+      const args = ['test', '--spec', '-w', '4'];
+      const jestArgv = buildJestArgv(mockValidatedConfig({ flags: parseFlags(args) }));
+      expect(jestArgv.maxWorkers).toBe(4);
+    });
+
+    it('should support the string Jest alias "-t" for testNamePattern', () => {
+      const args = ['test', '--spec', '-t=my-test-pattern'];
+      const jestArgv = buildJestArgv(mockValidatedConfig({ flags: parseFlags(args) }));
+      expect(jestArgv.testNamePattern).toBe('my-test-pattern');
+    });
+
+    it('should support the string Jest alias "-t pattern" for testNamePattern', () => {
+      const args = ['test', '--spec', '-t', 'my-test-pattern'];
+      const jestArgv = buildJestArgv(mockValidatedConfig({ flags: parseFlags(args) }));
+      expect(jestArgv.testNamePattern).toBe('my-test-pattern');
+    });
+
+    it.each<[string, keyof Config.Argv]>([
+      ['b', 'bail'],
+      ['e', 'expand'],
+      ['o', 'onlyChanged'],
+      ['f', 'onlyFailures'],
+      ['i', 'runInBand'],
+      ['u', 'updateSnapshot'],
+    ])('should support the boolean Jest alias %p for %p', (alias, fullArgument) => {
+      const args = ['test', '--spec', `-${alias}`];
+      const jestArgv = buildJestArgv(mockValidatedConfig({ flags: parseFlags(args) }));
+      expect(jestArgv[fullArgument]).toBe(true);
+    });
+  });
 });