Introduce async/await

exceljs · guyonroche · Sep 2, 2019 · May 22, 2019 · May 22, 2019 · Aug 21, 2019
commit f66531dc276bf4cf3b1615478603a77440c82c0a
diff --git a/.eslintrc b/.eslintrc
@@ -32,7 +32,7 @@
     "prefer-rest-params": ["off"],
     "quotes": ["error", "single"],
     "semi": ["error", "always"],
-    "space-before-function-paren": ["error", "never"],
+    "space-before-function-paren": ["error", {"anonymous": "never", "named": "never", "asyncArrow": "always"}],
     "strict": ["off"],
     "class-methods-use-this": ["off"],
     "no-return-assign": ["off"],

diff --git a/.prettier b/.prettier
@@ -1,5 +1,6 @@
 {
   "bracketSpacing": false,
   "printWidth": 160,
-  "trailingComma": "all"
+  "trailingComma": "all",
+  "bracketSpacing": false
 }
diff --git a/lib/csv/csv.js b/lib/csv/csv.js
@@ -28,23 +28,16 @@ const SpecialValues = {
 /* eslint-ensable quote-props */
 
 CSV.prototype = {
-  readFile(filename, options) {
+  async readFile(filename, options) {
     const self = this;
     options = options || {};
-    let stream;
-    return utils.fs
-      .exists(filename)
-      .then(exists => {
-        if (!exists) {
-          throw new Error(`File not found: ${filename}`);
-        }
-        stream = fs.createReadStream(filename);
-        return self.read(stream, options);
-      })
-      .then(worksheet => {
-        stream.close();
-        return worksheet;
-      });
+    if (!(await utils.fs.exists(filename))) {
+      throw new Error(`File not found: ${filename}`);
+    }
+    const stream = fs.createReadStream(filename);
+    const worksheet = await self.read(stream, options);
+    stream.close();
+    return worksheet;
   },
   read(stream, options) {
     options = options || {};
@@ -163,9 +156,10 @@ CSV.prototype = {
 
     return this.write(stream, options);
   },
-  writeBuffer(options) {
+  async writeBuffer(options) {
     const self = this;
     const stream = new StreamBuf();
-    return self.write(stream, options).then(() => stream.read());
+    await self.write(stream, options);
+    return stream.read();
   },
 };
diff --git a/lib/stream/xlsx/sheet-rels-writer.js b/lib/stream/xlsx/sheet-rels-writer.js
@@ -76,7 +76,8 @@ SheetRelsWriter.prototype = {
   // ================================================================================
   _writeOpen() {
     this.stream.write(
-      '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>' + '<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">'
+      `<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+       <Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">`
     );
   },
   _writeRelationship(relationship) {
@@ -88,14 +89,14 @@ SheetRelsWriter.prototype = {
 
     if (relationship.TargetMode) {
       this.stream.write(
-        `${'<Relationship' + ' Id="'}${rId}"` +
+        `<Relationship Id="${rId}"` +
           ` Type="${relationship.Type}"` +
           ` Target="${utils.xmlEncode(relationship.Target)}"` +
           ` TargetMode="${relationship.TargetMode}"` +
           '/>'
       );
     } else {
-      this.stream.write(`${'<Relationship' + ' Id="'}${rId}"` + ` Type="${relationship.Type}"` + ` Target="${relationship.Target}"` + '/>');
+      this.stream.write(`<Relationship Id="${rId}" Type="${relationship.Type}" Target="${relationship.Target}"/>`);
     }
 
     return rId;

diff --git a/lib/stream/xlsx/workbook-writer.js b/lib/stream/xlsx/workbook-writer.js
@@ -96,15 +96,13 @@ WorkbookWriter.prototype = {
     return PromiseLib.Promise.resolve();
   },
 
-  commit() {
+  async commit() {
     // commit all worksheets, then add suplimentary files
-    return this.promise
-      .then(() => this._commitWorksheets())
-      .then(() =>
-        PromiseLib.Promise.all([this.addContentTypes(), this.addApp(), this.addCore(), this.addSharedStrings(), this.addStyles(), this.addWorkbookRels()])
-      )
-      .then(() => this.addWorkbook())
-      .then(() => this._finalize());
+    await this.promise;
+    await this._commitWorksheets();
+    await PromiseLib.Promise.all([this.addContentTypes(), this.addApp(), this.addCore(), this.addSharedStrings(), this.addStyles(), this.addWorkbookRels()]);
+    await this.addWorkbook();
+    return this._finalize();
   },
   get nextId() {
     // find the next unique spot to add worksheet

diff --git a/lib/utils/flow-control.js b/lib/utils/flow-control.js
@@ -29,7 +29,7 @@ class FlowControl extends events.EventEmitter {
 
     // determine timeout for flow control delays
     if (options.gc) {
-      const {gc} = options;
+      const { gc } = options;
       if (gc.getTimeout) {
         this.getTimeout = gc.getTimeout;
       } else {
@@ -77,7 +77,7 @@ class FlowControl extends events.EventEmitter {
     });
   }
 
-  _pipe(chunk) {
+  async _pipe(chunk) {
     // Write chunk to all pipes. A chunk with no data is the end
     const promises = [];
     this.pipes.forEach(pipe => {
@@ -94,13 +94,12 @@ class FlowControl extends events.EventEmitter {
     if (!promises.length) {
       promises.push(PromiseLib.Promise.resolve());
     }
-    return PromiseLib.Promise.all(promises).then(() => {
-      try {
-        chunk.callback();
-      } catch (e) {
-        // quietly ignore
-      }
-    });
+    await PromiseLib.Promise.all(promises);
+    try {
+      chunk.callback();
+    } catch (e) {
+      // quietly ignore
+    }
   }
 
   _animate() {
@@ -127,19 +126,17 @@ class FlowControl extends events.EventEmitter {
     return PromiseLib.Promise.resolve();
   }
 
-  _flush() {
+  async _flush() {
     // If/while not corked and we have buffers to send, send them
     if (this.queue && !this.flushing && !this.corked) {
       if (this.queue.length) {
         this.flushing = true;
-        this._delay()
-          .then(() => this._pipe(this.queue.shift()))
-          .then(() => {
-            setImmediate(() => {
-              this.flushing = false;
-              this._flush();
-            });
-          });
+        await this._delay();
+        await this._pipe(this.queue.shift());
+        setImmediate(() => {
+          this.flushing = false;
+          this._flush();
+        });
       }
 
       if (!this.stem) {

diff --git a/lib/utils/stream-buf.js b/lib/utils/stream-buf.js
@@ -201,16 +201,15 @@ utils.inherits(StreamBuf, Stream.Duplex, {
     return buf;
   },
 
-  _pipe(chunk) {
+  async _pipe(chunk) {
     const write = function(pipe) {
       return new PromiseLib.Promise(resolve => {
         pipe.write(chunk.toBuffer(), () => {
           resolve();
         });
       });
     };
-    const promises = this.pipes.map(write);
-    return promises.length ? PromiseLib.Promise.all(promises).then(utils.nop) : PromiseLib.Promise.resolve();
+    await Promise.all(this.pipes.map(write));
   },
   _writeToBuffers(chunk) {
     let inPos = 0;
@@ -223,7 +222,7 @@ utils.inherits(StreamBuf, Stream.Duplex, {
       inPos += buffer.write(chunk, inPos, inLen - inPos);
     }
   },
-  write(data, encoding, callback) {
+  async write(data, encoding, callback) {
     if (encoding instanceof Function) {
       callback = encoding;
       encoding = 'utf8';
@@ -249,7 +248,8 @@ utils.inherits(StreamBuf, Stream.Duplex, {
           this._pipe(this.buffers.shift());
         }
       } else if (!this.corked) {
-        this._pipe(chunk).then(callback);
+        await this._pipe(chunk);
+        callback();
       } else {
         this._writeToBuffers(chunk);
         process.nextTick(callback);

diff --git a/lib/utils/zip-stream.js b/lib/utils/zip-stream.js
@@ -1,6 +1,5 @@
 const events = require('events');
 const JSZip = require('jszip');
-const PromiseLib = require('./promise');
 
 const StreamBuf = require('./stream-buf');
 
@@ -27,44 +26,40 @@ class ZipReader extends events.EventEmitter {
 
   _finished() {
     if (!--this.count) {
-      PromiseLib.Promise.resolve().then(() => {
+      process.nextTick(() => {
         this.emit('finished');
       });
     }
   }
 
-  _process() {
-    const content = this.stream.read();
-    this.jsZip
-      .loadAsync(content)
-      .then(zip => {
-        zip.forEach((path, entry) => {
-          if (!entry.dir) {
-            this.count++;
-            entry
-              .async(this.getEntryType(path))
-              .then(data => {
-                const entryStream = new StreamBuf();
-                entryStream.path = path;
-                entryStream.write(data);
-                entryStream.autodrain = () => {
-                  this._finished();
-                };
-                entryStream.on('finish', () => {
-                  this._finished();
-                });
-
-                this.emit('entry', entryStream);
-              })
-              .catch(error => {
-                this.emit('error', error);
-              });
+  async _process() {
+    try {
+      const content = this.stream.read();
+      const zip = await this.jsZip.loadAsync(content);
+      zip.forEach(async (path, entry) => {
+        if (!entry.dir) {
+          this.count++;
+          try {
+            const data = await entry.async(this.getEntryType(path));
+            const entryStream = new StreamBuf();
+            entryStream.path = path;
+            entryStream.write(data);
+            entryStream.autodrain = () => {
+              this._finished();
+            };
+            entryStream.on('finish', () => {
+              this._finished();
+            });
+
+            this.emit('entry', entryStream);
+          } catch (error) {
+            this.emit('error', error);
           }
-        });
-      })
-      .catch(error => {
-        this.emit('error', error);
+        }
       });
+    } catch (error) {
+      this.emit('error', error);
+    }
   }
 
   // ==========================================================================
@@ -121,11 +116,10 @@ class ZipWriter extends events.EventEmitter {
     }
   }
 
-  finalize() {
-    return this.zip.generateAsync(this.options).then(content => {
-      this.stream.end(content);
-      this.emit('finish');
-    });
+  async finalize() {
+    const content = await this.zip.generateAsync(this.options);
+    this.stream.end(content);
+    this.emit('finish');
   }
 
   // ==========================================================================

diff --git a/lib/xlsx/xform/base-xform.js b/lib/xlsx/xform/base-xform.js
@@ -52,10 +52,7 @@ class BaseXform {
 
   mergeModel(obj) {
     // set obj's props to this.model
-    this.model = Object.assign(
-      this.model || {},
-      obj
-    );
+    this.model = Object.assign(this.model || {}, obj);
   }
 
   parse(parser, stream) {