Update wasm_offset_converter. NFC (emscripten-core#24588)

- Convert to ES class
- Use string templates

Author: sbc100

src/source_map_support.js

@@ -4,96 +4,95 @@
  * SPDX-License-Identifier: MIT
  */
 
-/**
- * @constructor
- */
-function WasmSourceMap(sourceMap) {
-  this.version = sourceMap.version;
-  this.sources = sourceMap.sources;
-  this.names = sourceMap.names;
+class WasmSourceMap {
+  mapping = {};
+  offsets = [];
 
-  this.mapping = {};
-  this.offsets = [];
+  constructor(sourceMap) {
+    this.version = sourceMap.version;
+    this.sources = sourceMap.sources;
+    this.names = sourceMap.names;
 
-  var vlqMap = {};
-  'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='.split('').forEach((c, i) => vlqMap[c] = i);
+    var vlqMap = {};
+    'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='.split('').forEach((c, i) => vlqMap[c] = i);
 
-  // based on https://github.com/Rich-Harris/vlq/blob/master/src/vlq.ts
-  function decodeVLQ(string) {
-    var result = [];
-    var shift = 0;
-    var value = 0;
+    // based on https://github.com/Rich-Harris/vlq/blob/master/src/vlq.ts
+    function decodeVLQ(string) {
+      var result = [];
+      var shift = 0;
+      var value = 0;
 
-    for (var i = 0; i < string.length; ++i) {
-      var integer = vlqMap[string[i]];
-      if (integer === undefined) {
-        throw new Error('Invalid character (' + string[i] + ')');
-      }
+      for (var ch of string) {
+        var integer = vlqMap[ch];
+        if (integer === undefined) {
+          throw new Error(`Invalid character (${ch})`);
+        }
 
-      value += (integer & 31) << shift;
+        value += (integer & 31) << shift;
 
-      if (integer & 32) {
-        shift += 5;
-      } else {
-        var negate = value & 1;
-        value >>= 1;
-        result.push(negate ? -value : value);
-        value = shift = 0;
+        if (integer & 32) {
+          shift += 5;
+        } else {
+          var negate = value & 1;
+          value >>= 1;
+          result.push(negate ? -value : value);
+          value = shift = 0;
+        }
       }
+      return result;
     }
-    return result;
-  }
 
-  var offset = 0, src = 0, line = 1, col = 1, name = 0;
-  sourceMap.mappings.split(',').forEach(function (segment, index) {
-    if (!segment) return;
-    var data = decodeVLQ(segment);
-    var info = {};
+    var offset = 0, src = 0, line = 1, col = 1, name = 0;
+    sourceMap.mappings.split(',').forEach(function (segment, index) {
+      if (!segment) return;
+      var data = decodeVLQ(segment);
+      var info = {};
 
-    offset += data[0];
-    if (data.length >= 2) info.source = src += data[1];
-    if (data.length >= 3) info.line = line += data[2];
-    if (data.length >= 4) info.column = col += data[3];
-    if (data.length >= 5) info.name = name += data[4];
-    this.mapping[offset] = info;
-    this.offsets.push(offset);
-  }, this);
-  this.offsets.sort((a, b) => a - b);
-}
+      offset += data[0];
+      if (data.length >= 2) info.source = src += data[1];
+      if (data.length >= 3) info.line = line += data[2];
+      if (data.length >= 4) info.column = col += data[3];
+      if (data.length >= 5) info.name = name += data[4];
+      this.mapping[offset] = info;
+      this.offsets.push(offset);
+    }, this);
+    this.offsets.sort((a, b) => a - b);
+  }
 
-WasmSourceMap.prototype.lookup = function (offset) {
-  var normalized = this.normalizeOffset(offset);
+  lookup(offset) {
+    var normalized = this.normalizeOffset(offset);
 #if USE_OFFSET_CONVERTER
-  if (!wasmOffsetConverter.isSameFunc(offset, normalized)) {
-    return null;
-  }
+    if (!wasmOffsetConverter.isSameFunc(offset, normalized)) {
+      return null;
+    }
 #endif
-  var info = this.mapping[normalized];
-  if (!info) {
-    return null;
+    var info = this.mapping[normalized];
+    if (!info) {
+      return null;
+    }
+    return {
+      file: this.sources[info.source],
+      line: info.line,
+      column: info.column,
+      name: this.names[info.name],
+    };
   }
-  return {
-    file: this.sources[info.source],
-    line: info.line,
-    column: info.column,
-    name: this.names[info.name],
-  };
-}
 
-WasmSourceMap.prototype.normalizeOffset = function (offset) {
-  var lo = 0;
-  var hi = this.offsets.length;
-  var mid;
+  normalizeOffset(offset) {
+    var lo = 0;
+    var hi = this.offsets.length;
+    var mid;
 
-  while (lo < hi) {
-    mid = Math.floor((lo + hi) / 2);
-    if (this.offsets[mid] > offset) {
-      hi = mid;
-    } else {
-      lo = mid + 1;
+    while (lo < hi) {
+      mid = Math.floor((lo + hi) / 2);
+      if (this.offsets[mid] > offset) {
+        hi = mid;
+      } else {
+        lo = mid + 1;
+      }
     }
+    return this.offsets[lo - 1];
   }
-  return this.offsets[lo - 1];
 }
 
 var wasmSourceMapFile = '{{{ WASM_BINARY_FILE }}}.map';