dedent: simplify implementation (#3079)

Author: IvanGoncharov

src/__testUtils__/dedent.js

@@ -30,17 +30,10 @@ export function dedent(
   strings: $ReadOnlyArray<string>,
   ...values: $ReadOnlyArray<string>
 ): string {
-  let str = '';
+  let str = strings[0];
 
-  for (let i = 0; i < strings.length; ++i) {
-    str += strings[i];
-    if (i < values.length) {
-      // istanbul ignore next (Ignore else inside Babel generated code)
-      const value = values[i];
-
-      str += value; // interpolation
-    }
+  for (let i = 1; i < strings.length; ++i) {
+    str += values[i - 1] + strings[i]; // interpolation
   }
-
   return dedentString(str);
 }

src/utilities/__tests__/printSchema-test.js

@@ -1,7 +1,7 @@
 import { expect } from 'chai';
 import { describe, it } from 'mocha';
 
-import { dedent } from '../../__testUtils__/dedent';
+import { dedent, dedentString } from '../../__testUtils__/dedent';
 
 import { DirectiveLocation } from '../../language/directiveLocation';
 
@@ -158,7 +158,7 @@ describe('Type System Printer', () => {
 
     expectPrintedSchema(schema).to.equal(
       // $FlowFixMe[incompatible-call]
-      dedent(String.raw`
+      dedentString(String.raw`
         type Query {
           singleField(argOne: String = "tes\t de\fault"): String
         }