Detect code duplicates in make-check run

It uses jscpd project by invoking it using npm script
"duplication". For now set minimum lines to report
as 26, because we have some 25 line duplicates.
Later we can reduce that number.

Signed-off-by: Szymon Kłos <szymon.klos@collabora.com>
Change-Id: I20e0ba9a07528e15a65f01d2247420da33339749

browser/.gitignore

@@ -8,8 +8,10 @@ index.html
 bower.json
 component.json
 
+mocha.log
 mocha_tests/*.js
 tscompile.done
+duplication.log
 
 _site
 dist/*.js

browser/Makefile.am

@@ -797,6 +797,7 @@ build-tests: $(MOCHA_TS_JS_FILES)
 	@echo "Build of mocha test finished."
 
 MOCHA_TEST_LOG = "`pwd`/mocha.log"
+DUPLICATION_TEST_LOG = "`pwd`/duplication.log"
 check-local: $(MOCHA_TS_JS_FILES)
 	@echo "Running mocha tests..."
 	@echo > ${MOCHA_TEST_LOG}
@@ -806,6 +807,14 @@ check-local: $(MOCHA_TS_JS_FILES)
 		cat ${MOCHA_TEST_LOG}; \
 		exit 1; \
 	fi
+	@echo "Checking code duplication..."
+	@echo > ${DUPLICATION_TEST_LOG}
+	@if npm run duplication 2> ${DUPLICATION_TEST_LOG} 1>&2; then \
+		echo "Code duplication tests finished successfully."; \
+	else \
+		cat ${DUPLICATION_TEST_LOG}; \
+		exit 1; \
+	fi
 
 # the delay (in milliseconds) between each emulated key stroke for each view
 typing_speed=100

browser/package.json

@@ -20,6 +20,7 @@
     "jquery-contextmenu": "2.9.2",
     "jquery-mousewheel": "3.1.13",
     "jquery-ui": "1.13.2",
+    "jscpd": "3.5.9",
     "l10n-for-node": "0.0.1",
     "mocha": "8.2.1",
     "pako": "2.0.4",
@@ -49,6 +50,7 @@
   },
   "scripts": {
     "test": "mocha 'mocha_tests/**/*.js'",
-    "test-single": "mocha"
+    "test-single": "mocha",
+    "duplication": "jscpd ./src/ --exitCode 1 --min-lines 26"
   }
 }