move error matcher definition into dedicated file

src/codeql.ts

@@ -12,6 +12,7 @@ import uuidV4 from 'uuid/v4';
 
 import * as api from './api-client';
 import * as defaults from './defaults.json'; // Referenced from codeql-action-sync-tool!
+import { errorMatchers} from './error_matcher';
 import { exec_wrapper } from './exec_wrapper';
 import { Language } from './languages';
 import * as util from './util';
@@ -390,7 +391,7 @@ function getCodeQLForCmd(cmd: string): CodeQL {
           '--',
           traceCommand
         ],
-        [[0, new RegExp("(No source code was seen during the build\\.|No JavaScript or TypeScript code found\\.)"), 'foo bar']]
+        errorMatchers
       );
     },
     finalizeDatabase: async function(databasePath: string) {
@@ -401,7 +402,7 @@ function getCodeQLForCmd(cmd: string): CodeQL {
           ...getExtraOptionsFromEnv(['database', 'finalize']),
           databasePath
         ],
-        [[0, new RegExp("(No source code was seen during the build\\.|No JavaScript or TypeScript code found\\.)"), 'foo bar']]);
+        errorMatchers);
     },
     resolveQueries: async function(queries: string[], extraSearchPath: string | undefined) {
       const codeqlArgs = [

src/error_matcher.ts

@@ -0,0 +1,19 @@
+
+export type ErrorMatcher = [number|null, RegExp|null, string];
+
+const namedMatchers: { [key: string]: ErrorMatcher } = {
+  noSourceCodeFound: [
+    32,
+    null,
+    `No source code was seen during the build. Please see...
+https://docs.github.com/en/github/finding-security-vulnerabilities-and-errors-in-your-code/troubleshooting-code-scanning#no-code-found-during-the-build`
+  ],
+  noSourceCodeFoundJavascript: [
+    null,
+    new RegExp("No JavaScript or TypeScript code found\\."),
+    `No source code was seen during the build. Please see...
+https://docs.github.com/en/github/finding-security-vulnerabilities-and-errors-in-your-code/troubleshooting-code-scanning#no-code-found-during-the-build`
+  ]
+};
+
+export const errorMatchers = Object.values(namedMatchers);

src/exec_wrapper.test.ts

@@ -1,7 +1,8 @@
 import * as exec from '@actions/exec';
 import test from 'ava';
 
-import { exec_wrapper, ErrorMatcher } from './exec_wrapper';
+import { ErrorMatcher } from './error_matcher';
+import { exec_wrapper } from './exec_wrapper';
 import {setupTests} from './testing-utils';
 // import fs from 'fs';
 

src/exec_wrapper.ts

@@ -1,8 +1,7 @@
 import * as exec from '@actions/exec';
 import * as im from '@actions/exec/lib/interfaces';
 
-
-export type ErrorMatcher = [number, RegExp, string];
+import {ErrorMatcher} from './error_matcher';
 
 /**
  * Wrapper for exec.exec which checks for specific return code and/or regex matches in console output.
@@ -64,7 +63,7 @@ export async function exec_wrapper(commandLine: string, args?: string[],
 
   if (matchers) {
     for (const [customCode, regex, message] of matchers) {
-      if (customCode === returnState || regex.test(stderr) || regex.test(stdout) ) {
+      if (customCode === returnState || regex && (regex.test(stderr) || regex.test(stdout)) ) {
         throw new Error(message);
       }
     }