refactor: rework JSON2CSVStreamParser to use callbacks

zemirco · Jan 22, 2022 · 50ed883 · 50ed883
1 parent d49cff4
commit 50ed883
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Showing 2 changed files with 29 additions and 17 deletions.
diff --git a/lib/JSON2CSVStreamParser.js b/lib/JSON2CSVStreamParser.js
@@ -27,7 +27,7 @@ class JSON2CSVStreamParser extends JSON2CSVBase {
   getObjectModeTokenizer() {
     return {
       write: (data) => this.pushLine(data),
-      end: () => {},
+      end: () => this.onEnd(),
     };
   }
 
@@ -48,11 +48,30 @@ class JSON2CSVStreamParser extends JSON2CSVBase {
         } else if (token === TokenType.LEFT_BRACE) {
           this.tokenParser = new TokenParser({ paths: ['$'], keepStack: false });
         } else {
-          throw new Error('Data should not be empty or the "fields" option should be included');
+          this.onError(new Error('Data should not be empty or the "fields" option should be included'));
+          return;
         }
 
         tokenizer.onToken = this.tokenParser.write.bind(this.tokenParser);
+        tokenizer.onError = this.onError.bind(this);
+        tokenizer.onEnd = () => {
+          if (!this.tokenParser.isEnded) this.tokenParser.end();
+        };
+
         this.tokenParser.onValue = (value) => this.pushLine(value);
+        this.tokenParser.onError = this.onError.bind(this);
+        this.tokenParser.onEnd = () => {
+          if (!this.tokenizer.isEnded) this.tokenizer.end();
+          if (!this._hasWritten) {
+            if (!this.opts.fields) {
+              this.onError(new Error('Data should not be empty or the "fields" option should be included'));
+              return;
+            }
+
+            this.pushHeader();
+    }
+          this.onEnd();
+        };
       }
 
       this.tokenParser.write(token, value, offset);
@@ -66,27 +85,15 @@ class JSON2CSVStreamParser extends JSON2CSVBase {
   }
 
   end() {
-    this.tokenizer.end();
-    if (this.tokenParser && !this.tokenParser.isEnded) {
-      this.tokenParser.end();
-    }
-    this.onEnd();
-
-    if (!this._hasWritten) {
-      if (!this.opts.fields) {
-        throw new Error('Data should not be empty or the "fields" option should be included');
-      }
-
-      this.pushHeader();
-    }
+    if (this.tokenizer && !this.tokenizer.isEnded) this.tokenizer.end();
   }
 
   /**
    * Generate the csv header and pushes it downstream.
    */
   pushHeader() {
     if (this.opts.withBOM) {
-      this.push('\ufeff');
+      this.onData('\ufeff');
     }
 
     if (this.opts.header) {
@@ -124,6 +131,7 @@ class JSON2CSVStreamParser extends JSON2CSVBase {
   onHeader(header) {}
   onLine(line) {}
   onData(data) {}
+  onError() {}
   onEnd() {}
   /* eslint-enable no-unused-vars */
 }

diff --git a/lib/JSON2CSVTransform.js b/lib/JSON2CSVTransform.js
@@ -27,8 +27,12 @@ class JSON2CSVTransform extends Transform {
     this.push(data);
   }
 
+  onError(err) {
+    throw err;
+  }
+
   onEnd() {
-    this.end.bind(this);
+    if (!this.writableEnded) this.end();
   }
 
   /**