Remove variable shadowing from the JavaScript files in the src/display/ folder

*This is part of a series of patches that will try to split PR 11566 into smaller chunks, to make reviewing more feasible.*

Once all the code has been fixed, we'll be able to eventually enable the ESLint no-shadow rule; see https://eslint.org/docs/rules/no-shadow

src/display/api.js

@@ -2343,7 +2343,7 @@ class WorkerTransport {
       this._onUnsupportedFeature.bind(this)
     );
 
-    messageHandler.on("JpegDecode", data => {
+    messageHandler.on("JpegDecode", ([imageUrl, components]) => {
       if (this.destroyed) {
         return Promise.reject(new Error("Worker was destroyed"));
       }
@@ -2354,7 +2354,6 @@ class WorkerTransport {
         return Promise.reject(new Error('"document" is not defined.'));
       }
 
-      const [imageUrl, components] = data;
       if (components !== 3 && components !== 1) {
         return Promise.reject(
           new Error("Only 3 components or 1 component can be returned")

src/display/canvas.js

@@ -367,11 +367,11 @@ function compileType3Glyph(imgData) {
     c.scale(1 / width, -1 / height);
     c.translate(0, -height);
     c.beginPath();
-    for (var i = 0, ii = outlines.length; i < ii; i++) {
+    for (let k = 0, kk = outlines.length; k < kk; k++) {
-      var o = outlines[i];
+      var o = outlines[k];
       c.moveTo(o[0], o[1]);
-      for (var j = 2, jj = o.length; j < jj; j += 2) {
+      for (let l = 2, ll = o.length; l < ll; l += 2) {
-        c.lineTo(o[j], o[j + 1]);
+        c.lineTo(o[l], o[l + 1]);
       }
     }
     c.fill();

src/display/content_disposition.js

@@ -115,13 +115,13 @@ function getFilenameFromContentDispositionHeader(contentDisposition) {
     }
     return value;
   }
-  function rfc2231getparam(contentDisposition) {
+  function rfc2231getparam(contentDispositionStr) {
     const matches = [];
     let match;
     // Iterate over all filename*n= and filename*n*= with n being an integer
     // of at least zero. Any non-zero number must not start with '0'.
     const iter = toParamRegExp("filename\\*((?!0\\d)\\d+)(\\*?)", "ig");
-    while ((match = iter.exec(contentDisposition)) !== null) {
+    while ((match = iter.exec(contentDispositionStr)) !== null) {
       let [, n, quot, part] = match; // eslint-disable-line prefer-const
       n = parseInt(n, 10);
       if (n in matches) {
@@ -205,11 +205,11 @@ function getFilenameFromContentDispositionHeader(contentDisposition) {
     //        ... but Firefox permits ? and space.
     return value.replace(
       /=\?([\w-]*)\?([QqBb])\?((?:[^?]|\?(?!=))*)\?=/g,
-      function(_, charset, encoding, text) {
+      function(matches, charset, encoding, text) {
         if (encoding === "q" || encoding === "Q") {
           // RFC 2047 section 4.2.
           text = text.replace(/_/g, " ");
-          text = text.replace(/=([0-9a-fA-F]{2})/g, function(_, hex) {
+          text = text.replace(/=([0-9a-fA-F]{2})/g, function(match, hex) {
             return String.fromCharCode(parseInt(hex, 16));
           });
           return textdecode(charset, text);

src/display/node_stream.js

@@ -292,13 +292,13 @@ class BaseRangeReader {
   }
 }
 
-function createRequestOptions(url, headers) {
+function createRequestOptions(parsedUrl, headers) {
   return {
-    protocol: url.protocol,
+    protocol: parsedUrl.protocol,
-    auth: url.auth,
+    auth: parsedUrl.auth,
-    host: url.hostname,
+    host: parsedUrl.hostname,
-    port: url.port,
+    port: parsedUrl.port,
-    path: url.path,
+    path: parsedUrl.path,
     method: "GET",
     headers,
   };

src/display/pattern_helper.js

@@ -158,7 +158,7 @@ var createMeshCanvas = (function createMeshCanvasClosure() {
       var x2_ = Math.round(Math.max(xa, xb));
       var j = rowSize * y + x1_ * 4;
       for (var x = x1_; x <= x2_; x++) {
-        let k = (xa - x) / (xa - xb);
+        k = (xa - x) / (xa - xb);
         if (k < 0) {
           k = 0;
         } else if (k > 1) {

src/display/text_layer.js

@@ -182,6 +182,17 @@ var renderTextLayer = (function renderTextLayerClosure() {
     capability.resolve();
   }
 
+  function findPositiveMin(ts, offset, count) {
+    let result = 0;
+    for (let i = 0; i < count; i++) {
+      const t = ts[offset++];
+      if (t > 0) {
+        result = result ? Math.min(t, result) : t;
+      }
+    }
+    return result;
+  }
+
   function expand(task) {
     var bounds = task._bounds;
     var viewport = task._viewport;
@@ -208,38 +219,28 @@ var renderTextLayer = (function renderTextLayerClosure() {
       // Finding intersections with expanded box.
       var points = [[0, 0], [0, b.size[1]], [b.size[0], 0], b.size];
       var ts = new Float64Array(64);
-      points.forEach(function(p, i) {
+      points.forEach(function(p, j) {
         var t = Util.applyTransform(p, m);
-        ts[i + 0] = c && (e.left - t[0]) / c;
+        ts[j + 0] = c && (e.left - t[0]) / c;
-        ts[i + 4] = s && (e.top - t[1]) / s;
+        ts[j + 4] = s && (e.top - t[1]) / s;
-        ts[i + 8] = c && (e.right - t[0]) / c;
+        ts[j + 8] = c && (e.right - t[0]) / c;
-        ts[i + 12] = s && (e.bottom - t[1]) / s;
+        ts[j + 12] = s && (e.bottom - t[1]) / s;
 
-        ts[i + 16] = s && (e.left - t[0]) / -s;
+        ts[j + 16] = s && (e.left - t[0]) / -s;
-        ts[i + 20] = c && (e.top - t[1]) / c;
+        ts[j + 20] = c && (e.top - t[1]) / c;
-        ts[i + 24] = s && (e.right - t[0]) / -s;
+        ts[j + 24] = s && (e.right - t[0]) / -s;
-        ts[i + 28] = c && (e.bottom - t[1]) / c;
+        ts[j + 28] = c && (e.bottom - t[1]) / c;
 
-        ts[i + 32] = c && (e.left - t[0]) / -c;
+        ts[j + 32] = c && (e.left - t[0]) / -c;
-        ts[i + 36] = s && (e.top - t[1]) / -s;
+        ts[j + 36] = s && (e.top - t[1]) / -s;
-        ts[i + 40] = c && (e.right - t[0]) / -c;
+        ts[j + 40] = c && (e.right - t[0]) / -c;
-        ts[i + 44] = s && (e.bottom - t[1]) / -s;
+        ts[j + 44] = s && (e.bottom - t[1]) / -s;
 
-        ts[i + 48] = s && (e.left - t[0]) / s;
+        ts[j + 48] = s && (e.left - t[0]) / s;
-        ts[i + 52] = c && (e.top - t[1]) / -c;
+        ts[j + 52] = c && (e.top - t[1]) / -c;
-        ts[i + 56] = s && (e.right - t[0]) / s;
+        ts[j + 56] = s && (e.right - t[0]) / s;
-        ts[i + 60] = c && (e.bottom - t[1]) / -c;
+        ts[j + 60] = c && (e.bottom - t[1]) / -c;
       });
-      var findPositiveMin = function(ts, offset, count) {
-        var result = 0;
-        for (var i = 0; i < count; i++) {
-          var t = ts[offset++];
-          if (t > 0) {
-            result = result ? Math.min(t, result) : t;
-          }
-        }
-        return result;
-      };
       // Not based on math, but to simplify calculations, using cos and sin
       // absolute values to not exceed the box (it can but insignificantly).
       var boxScale = 1 + Math.min(Math.abs(c), Math.abs(s));