Simplify find context url code.

Author: dlongley

lib/context.js

@@ -1055,8 +1055,8 @@ async function _retrieveContextUrls(input, options) {
  */
 function _findContextUrls(input, urls, replace, base) {
   if(_isArray(input)) {
-    for(let i = 0; i < input.length; ++i) {
-      _findContextUrls(input[i], urls, replace, base);
+    for(const element of input) {
+      _findContextUrls(element, urls, replace, base);
     }
     return;
   }
@@ -1074,31 +1074,29 @@ function _findContextUrls(input, urls, replace, base) {
     }
 
     // get @context
-    let ctx = input[key];
+    const ctx = input[key];
 
     if(_isArray(ctx)) {
       // array @context
       let length = ctx.length;
       for(let i = 0; i < length; ++i) {
-        let _ctx = ctx[i];
+        const _ctx = ctx[i];
         if(_isString(_ctx)) {
-          _ctx = prependBase(base, _ctx);
+          const prepended = prependBase(base, _ctx);
+          const resolved = urls[prepended];
           // replace w/@context if requested
           if(replace) {
-            if(urls[_ctx] !== false) {
-              _ctx = urls[_ctx];
-              if(_isArray(_ctx)) {
-                // add flattened context
-                Array.prototype.splice.apply(ctx, [i, 1].concat(_ctx));
-                i += _ctx.length - 1;
-                length = ctx.length;
-              } else {
-                ctx[i] = _ctx;
-              }
+            if(_isArray(resolved)) {
+              // add flattened context
+              Array.prototype.splice.apply(ctx, [i, 1].concat(resolved));
+              i += resolved.length - 1;
+              length = ctx.length;
+            } else {
+              ctx[i] = resolved;
             }
-          } else if(!(_ctx in urls)) {
+          } else if(resolved === undefined) {
             // @context URL found
-            urls[_ctx] = false;
+            urls[prepended] = false;
           }
         } else {
           // look for scoped context
@@ -1111,15 +1109,16 @@ function _findContextUrls(input, urls, replace, base) {
       }
     } else if(_isString(ctx)) {
       // string @context
-      ctx = prependBase(base, ctx);
+      const prepended = prependBase(base, ctx);
+      const resolved = urls[prepended];
       // replace w/@context if requested
       if(replace) {
-        if(urls[ctx] !== false) {
-          input[key] = urls[ctx];
+        if(resolved !== false) {
+          input[key] = resolved;
         }
-      } else if(!(ctx in urls)) {
+      } else if(resolved === undefined) {
         // @context URL found
-        urls[ctx] = false;
+        urls[prepended] = false;
       }
     } else {
       // look for scoped context