fix(perf): address slow parse when using unknown-options-as-args (#394)

Author: Benjamin E. Coe

lib/yargs-parser.ts

@@ -210,6 +210,7 @@ export class YargsParser {
 
     for (let i = 0; i < args.length; i++) {
       const arg = args[i]
+      const truncatedArg = arg.replace(/^-{3,}/, '---')
       let broken: boolean
       let key: string | undefined
       let letters: string[]
@@ -221,7 +222,7 @@ export class YargsParser {
       if (arg !== '--' && isUnknownOptionAsArg(arg)) {
         pushPositional(arg)
       // ---, ---=, ----, etc,
-      } else if (arg.match(/---+(=|$)/)) {
+      } else if (truncatedArg.match(/---+(=|$)/)) {
         // options without key name are invalid.
         pushPositional(arg)
         continue
@@ -969,6 +970,7 @@ export class YargsParser {
     }
 
     function isUnknownOption (arg: string): boolean {
+      arg = arg.replace(/^-{3,}/, '--')
       // ignore negative numbers
       if (arg.match(negative)) { return false }
       // if this is a short option group and all of them are configured, it isn't unknown

test/yargs-parser.cjs

@@ -3963,4 +3963,37 @@ describe('yargs-parser', function () {
     }).to.throw(/yargs parser supports a minimum Node.js version of 55/)
     delete process.env.YARGS_MIN_NODE_VERSION
   })
+
+  // Refs: https://github.com/yargs/yargs-parser/issues/386
+  describe('perf', () => {
+    const i = 100000
+    describe('unknown-options-as-args', () => {
+      it('parses long chain of "-" with reasonable performance', function () {
+        this.timeout(500)
+        const s = (new Array(i).fill('-').join('')) + 'a'
+        const parsed = parser([s], { configuration: { 'unknown-options-as-args': true } })
+        parsed._[0].should.equal(s)
+      })
+      it('parses long chain of "-a-a" with reasonable performance', function () {
+        this.timeout(500)
+        const s = '-' + (new Array(i).fill('-a').join('')) + '=35'
+        const parsed = parser([s], { configuration: { 'unknown-options-as-args': true } })
+        parsed._[0].should.equal(s)
+      })
+    })
+    it('parses long chain of "-" with reasonable performance', function () {
+      this.timeout(500)
+      const s = (new Array(i).fill('-').join('')) + 'a'
+      const arg = (new Array(i - 2).fill('-').join('')) + 'a'
+      const parsed = parser([s])
+      parsed[arg].should.equal(true)
+    })
+    it('parses long chain of "-a-a" with reasonable performance', function () {
+      this.timeout(500)
+      const s = '-' + (new Array(i).fill('-a').join('')) + '=35'
+      const arg = 'a' + (new Array(i - 1).fill('A').join(''))
+      const parsed = parser([s])
+      parsed[arg].should.equal(35)
+    })
+  })
 })