Made JSON.stringify comptible with javascript JSON (#266)

* Made JSON.stringify comptible with javascript JSON The current JSON.stringify method escaped characters in a way that was NOT compatible with the current javascript JSON implementation. For example, the string single-character "\n" was being translated into: "\"\ \"" Instead of being stringifyed as: "\"\n\"". This is because the character \n was being added, instead of adding an "n" preceeded by an "\\". * Formatting assembly/JSON.ts Co-authored-by: Max Graey <[email protected]> Co-authored-by: Willem Wyndham <[email protected]>
DevCycleHQ · Aug 6, 2021 · 1edab43 · 1edab43
1 parent 71df6f7
commit 1edab43
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Showing 2 changed files with 37 additions and 37 deletions.
diff --git a/assembly/JSON.ts b/assembly/JSON.ts
@@ -182,25 +182,34 @@ export abstract class Value {
   }
 }
 
+function escapeChar(char: string): string {
+  const charCode = char.charCodeAt(0);
+  switch (charCode) {
+    case 0x22: return '\\"';
+    case 0x5C: return "\\\\";
+    case 0x08: return "\\b";
+    case 0x0A: return "\\n";
+    case 0x0D: return "\\r";
+    case 0x09: return "\\t";
+    case 0x0C: return "\\f";
+    case 0x0B: return "\\u000b";
+    default: return char;
+  }
+}
+
 export class Str extends Value {
+
   constructor(public _str: string) {
     super();
   }
 
   stringify(): string {
-    let escaped: i32[] = [];
+    let escaped: string[] = new Array(this._str.length);
     for (let i = 0; i < this._str.length; i++) {
-      const charCode = this._str.charCodeAt(i);
-      if (
-        charCode == 0x22 || // "    quotation mark  U+0022
-        charCode == 0x5C || // \    reverse solidus U+005C
-        charCode < 0x20 // control characters
-      ) {
-        escaped.push(0x5c); // add a reverse solidus (backslash) to escape reserved chars 
-      }
-      escaped.push(charCode);
+      const char = this._str.at(i);
+      escaped[i] = escapeChar(char);
     }
-    return "\"" + String.fromCharCodes(escaped) + "\"";
+    return `"${escaped.join('')}"`;
   }
 
   toString(): string {

diff --git a/assembly/__tests__/string_escape.spec.ts b/assembly/__tests__/string_escape.spec.ts
@@ -16,38 +16,29 @@ describe('Escaped characters', () => {
     ];
     strings.forEach((str) => {
       const jsonStr = new JSON.Str(str);
-      expect(jsonStr.stringify()).toBe('"' + str + '"');
+      expect(jsonStr.stringify()).toBe(`"${str}"`);
     });
   });
+
   it('Escapes quotes and backslashes', () => {
     const strings = ['"', '\\', '"\\"', '\\"\\"'];
-    strings.forEach((str) => {
-      const jsonStr = new JSON.Str(str);
-      expect(jsonStr.stringify()).toBe('"' + escaped(str) + '"');
-    });
+    // Computed using javascript's JSON as implemented in mozilla firefox 90.0 (64-bit)
+    const expected = ["\"\\\"\"", "\"\\\\\"", "\"\\\"\\\\\\\"\"", "\"\\\\\\\"\\\\\\\"\""];
+
+    for(let i=0; i<strings.length; i++){
+      const jsonStr = new JSON.Str(strings[i]);
+      expect(jsonStr.stringify()).toBe(expected[i]);
+    }
   });
+
   it('Escapes control characters', () => {
     const strings = ['\n', '\r', '\r\n', '\b', '\f', '\t', '\v', '\b\f\t\v\r'];
-    strings.forEach((str) => {
-      const jsonStr = new JSON.Str(str);
-      expect(jsonStr.stringify()).toBe('"' + escaped(str) + '"');
-    });
-  });
-});
+    // Computed using javascript's JSON as implemented in mozilla firefox 90.0 (64-bit)
+    const expected = ["\"\\n\"","\"\\r\"","\"\\r\\n\"","\"\\b\"","\"\\f\"","\"\\t\"","\"\\u000b\"","\"\\b\\f\\t\\u000b\\r\""];
 
-function escaped(str: string): string {
-  const escapedChars: i32[] = [];
-  for (let i = 0; i < str.length; i++) {
-    const charCode = str.charCodeAt(i);
-    if (
-      charCode < 0x20 || // control characters
-      charCode == 0x22 || // double quote (")
-      charCode == 0x5c
-    ) {
-      // backslash / reverse solidus (\)
-      escapedChars.push(0x5c);
+    for(let i=0; i<strings.length; i++){
+      const jsonStr = new JSON.Str(strings[i]);
+      expect(jsonStr.stringify()).toBe(expected[i]);
     }
-    escapedChars.push(charCode);
-  }
-  return String.fromCharCodes(escapedChars);
-}
+  });
+});