diff --git a/js/tests/using-filter_test.js b/js/tests/using-filter_test.js
index df5d4f920..b897bf450 100644
--- a/js/tests/using-filter_test.js
+++ b/js/tests/using-filter_test.js
@@ -7,7 +7,7 @@ const check = ({ filterCalls }, eq, a, b) => {
   filterCalls.length = 0
   return len ? result : false
 }
-
+//check that the code did use filter properly
 t(({ eq, ctx }) =>
   check(ctx, eq, filterShortStateName(ctx.arr1), [
     'Alaska',
@@ -23,7 +23,7 @@ t(({ eq, ctx }) =>
     'Utah',
   ]),
 )
-
+//check that the code did use filter properly
 t(({ eq, ctx }) =>
   check(ctx, eq, filterStartVowel(ctx.arr1), [
     'Alabama',
@@ -40,7 +40,7 @@ t(({ eq, ctx }) =>
     'Utah',
   ]),
 )
-
+//check that the code did use filter properly
 t(({ eq, ctx }) =>
   check(ctx, eq, filter5Vowels(ctx.arr1), [
     'California',
@@ -51,7 +51,7 @@ t(({ eq, ctx }) =>
     'West Virginia',
   ]),
 )
-
+//check that the code did use filter properly
 t(({ eq, ctx }) =>
   check(ctx, eq, filter1DistinctVowel(ctx.arr1), [
     'Alabama',
@@ -64,7 +64,7 @@ t(({ eq, ctx }) =>
     'Tennessee',
   ]),
 )
-
+//check that the code did use filter properly
 t(({ eq, ctx }) =>
   check(ctx, eq, multiFilter(ctx.arr2), [
     { tag: 'CA', name: 'California', capital: 'Sacramento', region: 'West' },
diff --git a/js/tests/using-map_test.js b/js/tests/using-map_test.js
index a12a107f8..9539eff57 100644
--- a/js/tests/using-map_test.js
+++ b/js/tests/using-map_test.js
@@ -16,6 +16,7 @@ t(({ eq, ctx }) =>
   ]),
 )
 
+//check that the code did use map properly
 t(({ eq, ctx }) => eq(ctx.mapCalls[0], ctx.states))
 
 // upperCasingStates
@@ -33,6 +34,7 @@ t(({ eq, ctx }) =>
   ]),
 )
 
+//check that the code did use map properly
 t(({ eq, ctx }) => eq(ctx.mapCalls.includes(ctx.cities), true))
 
 // fahrenheitToCelsius
@@ -48,6 +50,7 @@ t(({ eq, ctx }) =>
   ]),
 )
 
+//check that the code did use map properly
 t(({ eq, ctx }) => eq(ctx.mapCalls.includes(ctx.temps), true))
 
 // trimTemp
@@ -95,6 +98,7 @@ t(({ eq, ctx }) =>
   ]),
 )
 
+//check that the code did use map properly
 t(({ eq, ctx }) => eq(ctx.mapCalls.includes(ctx.states), true))
 
 // tempForecasts
diff --git a/js/tests/using-reduce_test.js b/js/tests/using-reduce_test.js
index 86eacf89c..55834e69f 100644
--- a/js/tests/using-reduce_test.js
+++ b/js/tests/using-reduce_test.js
@@ -2,37 +2,46 @@ export const tests = []
 const t = (f) => tests.push(f)
 
 t(({ eq }) => eq(adder([1, 2, 3, 4]), 10))
+//check that the code did use reduce properly
 t(({ eq, ctx }) =>
   eq(ctx.reduceCalls[ctx.reduceCalls.length - 1], [1, 2, 3, 4]),
 )
 t(({ eq }) => eq(adder([9, 24, 7, 11, 3], 10), 64))
+//check that the code did use reduce properly
 t(({ eq, ctx }) =>
   eq(ctx.reduceCalls[ctx.reduceCalls.length - 1], [9, 24, 7, 11, 3]),
 )
 t(({ eq }) => eq(adder([]), 0))
+//check that the code did use reduce properly
 t(({ eq, ctx }) => eq(ctx.reduceCalls[ctx.reduceCalls.length - 1], []))
 
 t(({ eq }) => eq(sumOrMul([29, 23, 3, 2, 25]), 135))
+//check that the code did use reduce properly
 t(({ eq, ctx }) =>
   eq(ctx.reduceCalls[ctx.reduceCalls.length - 1], [29, 23, 3, 2, 25]),
 )
 t(({ eq }) => eq(sumOrMul([18, 17, 7, 13, 25], 12), 278))
+//check that the code did use reduce properly
 t(({ eq, ctx }) =>
   eq(ctx.reduceCalls[ctx.reduceCalls.length - 1], [18, 17, 7, 13, 25]),
 )
 t(({ eq }) => eq(sumOrMul([8, 16, 7, 0, 32]), 0))
+//check that the code did use reduce properly
 t(({ eq, ctx }) =>
   eq(ctx.reduceCalls[ctx.reduceCalls.length - 1], [8, 16, 7, 0, 32]),
 )
 t(({ eq }) => eq(sumOrMul([8, 16, 7, 0, 31]), 31))
+//check that the code did use reduce properly
 t(({ eq, ctx }) =>
   eq(ctx.reduceCalls[ctx.reduceCalls.length - 1], [8, 16, 7, 0, 31]),
 )
 
 t(({ eq, ctx }) => eq(funcExec(ctx.fArr1, 10), `result: [137]`))
+//check that the code did use reduce properly
 t(({ eq, ctx }) => eq(ctx.reduceCalls[ctx.reduceCalls.length - 1], ctx.fArr1))
 
 t(({ eq, ctx }) => eq(funcExec(ctx.fArr2, 4), { result: 72, isOdd: true }))
+//check that the code did use reduce properly
 t(({ eq, ctx }) => eq(ctx.reduceCalls[ctx.reduceCalls.length - 1], ctx.fArr2))
 
 Object.freeze(tests)