fast-csv - npm Package Compare versions

Comparing version 3.2.0 to 3.3.0

build/src/formatter/formatter/RowFormatter.d.ts

@@ -12,3 +12,3 @@ import { FormatterOptions } from '../FormatterOptions';
     private headers;
-    private parsedHeaders;
+    private shouldWriteHeaders;
     private hasWrittenHeaders;
@@ -15,0 +15,0 @@ private rowCount;

build/src/formatter/formatter/RowFormatter.js

@@ -12,5 +12,5 @@ "use strict";
         this.headers = formatterOptions.headers;
-        this.parsedHeaders = formatterOptions.hasProvidedHeaders && Array.isArray(formatterOptions.headers);
-        this.hasWrittenHeaders = !formatterOptions.hasProvidedHeaders;
-        if (this.parsedHeaders && this.headers !== null) {
+        this.shouldWriteHeaders = formatterOptions.shouldWriteHeaders;
+        this.hasWrittenHeaders = false;
+        if (this.headers !== null) {
             this.fieldFormatter.headers = this.headers;
@@ -74,4 +74,5 @@ }
                 const { shouldFormatColumns, headers } = this.checkHeaders(transformedRow);
-                if (headers) {
+                if (this.shouldWriteHeaders && headers && !this.hasWrittenHeaders) {
                     rows.push(this.formatColumns(headers, true));
+                    this.hasWrittenHeaders = true;
                 }
@@ -89,25 +90,34 @@ if (shouldFormatColumns) {
     checkHeaders(row) {
-        if (!this.parsedHeaders) {
-            this.parsedHeaders = true;
-            this.headers = RowFormatter.gatherHeaders(row);
-            this.fieldFormatter.headers = this.headers;
+        if (this.headers) {
+            // either the headers were provided by the user or we have already gathered them.
+            return { shouldFormatColumns: true, headers: this.headers };
         }
-        if (this.hasWrittenHeaders) {
+        const headers = RowFormatter.gatherHeaders(row);
+        this.headers = headers;
+        this.fieldFormatter.headers = headers;
+        if (!this.shouldWriteHeaders) {
+            // if we are not supposed to write the headers then
+            // alwyas format the columns
             return { shouldFormatColumns: true, headers: null };
         }
-        this.hasWrittenHeaders = true;
-        const shouldFormatColumns = RowFormatter.isHashArray(row) || !Array.isArray(row);
-        return { shouldFormatColumns, headers: this.headers };
+        // if the row is equal to headers dont format
+        return { shouldFormatColumns: !lodash_1.isEqual(headers, row), headers };
     }
     gatherColumns(row) {
+        if (this.headers === null) {
+            throw new Error('Headers is currently null');
+        }
         if (!Array.isArray(row)) {
-            if (this.headers === null) {
-                throw new Error('Headers is currently null');
-            }
             return this.headers.map((header) => row[header]);
         }
         if (RowFormatter.isHashArray(row)) {
-            return row.map((col) => col[1]);
+            return this.headers.map((header, i) => {
+                const col = row[i];
+                if (col) {
+                    return col[1];
+                }
+                return '';
+            });
         }
-        return row;
+        return this.headers.map((header, i) => row[i]);
     }
@@ -114,0 +124,0 @@ callTransformer(row, cb) {

build/src/formatter/FormatterOptions.d.ts

@@ -29,3 +29,3 @@ import { RowTransformFunction } from './types';
     readonly transform: RowTransformFunction | null;
-    readonly hasProvidedHeaders: boolean;
+    readonly shouldWriteHeaders: boolean;
     readonly escapedQuote: string;
@@ -32,0 +32,0 @@ constructor(opts?: FormatterOptionsArgs);

build/src/formatter/FormatterOptions.js

@@ -24,3 +24,3 @@ "use strict";
         }
-        this.hasProvidedHeaders = !!this.headers;
+        this.shouldWriteHeaders = !!this.headers;
         this.headers = Array.isArray(this.headers) ? this.headers : null;
@@ -27,0 +27,0 @@ this.escapedQuote = `${this.escape}${this.quote}`;

docs/formatting.md

@@ -17,2 +17,11 @@ # Formatting
     * [Alternate `escape`](#examples-alternate-escape)
+    * [Headers](#examples-headers)
+      * Auto Discovery
+        * [Object Rows](#headers-auto-discover-object)
+        * [Hash Array Rows](#headers-auto-discover-hash-array)
+      * Provide Headers
+        * [Array Rows](#headers-provided-array)
+        * [Hash Array Rows](#headers-provided-hash-array)
+        * [Object Rows - Reorder Columns](#headers-provided-object)
+        * [Object Rows - Remove Columns](#headers-provided-object-remove-column)
     * [`quoteColumns`](#examples-quote-columns)
@@ -35,5 +44,8 @@ * [`quoteHeaders`](#examples-quote-headers)
   *  If true then the headers will be auto detected from the first row. 
-    * If the row is an object then the keys will be used.
-    * If the row is an array of two element arrays (`[ ['header', 'column'], ['header2', 'column2'] ]`) then the first element in each array will be used.
+      * If the row is a one-dimensional array then headers is a no-op
+      * If the row is an object then the keys will be used.
+      * If the row is an array of two element arrays (`[ ['header', 'column'], ['header2', 'column2'] ]`) then the first element in each array will be used.
   *  If there is not a headers row and you want to provide one then set to a `string[]`
+      * **NOTE** If the row is an object the headers must match fields in the object, otherwise you will end up with empty fields
+      * **NOTE** If there are more headers than columns then additional empty columns will be added
 * `quoteColumns: {boolean|boolean[]|{[string]: boolean} = false`
@@ -336,2 +348,191 @@ * If `true` then columns and headers will be quoted (unless `quoteHeaders` is specified).
 
+<a name="examples-headers"></a>
+
+### Headers
+
+#### Auto Discovery
+
+`fast-csv` will auto-discover headers when the `headers` option is set to `true`.
+
+**NOTE** When working is one-dimensional array rows (e.g. `[ 'a', 'b', 'c' ]`) this is a no-op.
+
+<a name="headers-auto-discover-object"></a>
+[`examples/formatting/headers_auto_discovery_object.example.js`](../examples/formatting/headers_auto_discovery_object.example.js)
+
+In this example the headers are auto-discovered from the objects passed in.
+
+```js
+const csvStream = csv.format({ headers: true});
+
+csvStream
+    .pipe(process.stdout)
+    .on('end', process.exit);
+
+csvStream.write({ header1: 'value1a', header2: 'value1b' });
+csvStream.write({ header1: 'value2a', header2: 'value2b' });
+csvStream.write({ header1: 'value3a', header2: 'value3b' });
+csvStream.write({ header1: 'value4a', header2: 'value4b' });
+csvStream.end();
+```
+
+Expected Output: 
+```
+header1,header2
+value1a,value1b
+value2a,value2b
+value3a,value3b
+value4a,value4b
+```
+
+<a name="headers-auto-discover-hash-array"></a>
+[`examples/formatting/headers_auto_discovery_hash_array.example.js`](../examples/formatting/headers_auto_discovery_hash_array.example.js)
+
+In this example the headers are auto-discovered from the hash arrays passed in.
+
+```js
+const csvStream = csv.format({ headers: true });
+
+csvStream
+    .pipe(process.stdout)
+    .on('end', process.exit);
+
+csvStream.write([ [ 'header1', 'value1a' ], [ 'header2', 'value1b' ] ]);
+csvStream.write([ [ 'header1', 'value2a' ], [ 'header2', 'value2b' ] ]);
+csvStream.write([ [ 'header1', 'value3a' ], [ 'header2', 'value3b' ] ]);
+csvStream.write([ [ 'header1', 'value4a' ], [ 'header2', 'value4b' ] ]);
+csvStream.end();
+```
+
+Expected Output: 
+```
+header1,header2
+value1a,value1b
+value2a,value2b
+value3a,value3b
+value4a,value4b
+```
+
+### Provided Headers
+
+You can also provide a set of `headers` by providing an array. This allows you to 
+
+* Reorder and/or exclude columns when working when object rows.
+* Rename  and/or exclude columns when working with hash array rows.
+* Specify headers or remove columns when working with array rows.
+
+**NOTE** When working with objects the header names should match keys. The headers option allows you to specify column order.
+
+<a name="headers-provided-array"></a>
+[`examples/formatting/headers_provided_array.example.js`](../examples/formatting/headers_provided_array.example.js)
+
+In this example a custom set of headers is provided for rows that are arrays.
+
+```js
+const csvStream = csv.format({ headers: [ 'header1', 'header2' ] });
+
+csvStream
+    .pipe(process.stdout)
+    .on('end', process.exit);
+
+csvStream.write([ 'value1a', 'value1b' ]);
+csvStream.write([ 'value2a', 'value2b' ]);
+csvStream.write([ 'value3a', 'value3b' ]);
+csvStream.write([ 'value4a', 'value4b' ]);
+csvStream.end();
+```
+
+Expected Output: 
+```
+header1,header2
+value1a,value1b
+value2a,value2b
+value3a,value3b
+value4a,value4b
+```
+
+<a name="headers-provided-hash-array"></a>
+[`examples/formatting/headers_provided_hash_array.example.js`](../examples/formatting/headers_provided_hash_array.example.js)
+
+In this example the headers are overridden with a custom set of headers
+
+```js
+const csvStream = csv.format({ headers: [ 'header1', 'header2' ] });
+
+csvStream
+    .pipe(process.stdout)
+    .on('end', process.exit);
+
+csvStream.write([ [ 'h1', 'value1a' ], [ 'h2', 'value1b' ] ]);
+csvStream.write([ [ 'h1', 'value2a' ], [ 'h2', 'value2b' ] ]);
+csvStream.write([ [ 'h1', 'value3a' ], [ 'h2', 'value3b' ] ]);
+csvStream.write([ [ 'h1', 'value4a' ], [ 'h2', 'value4b' ] ]);
+csvStream.end();
+```
+
+Expected Output: 
+```
+header1,header2
+value1a,value1b
+value2a,value2b
+value3a,value3b
+value4a,value4b
+```
+
+<a name="headers-provided-object"></a>
+[`examples/formatting/headers_provided_object.example.js`](../examples/formatting/headers_provided_object.example.js)
+
+In this example the columns are reordered.
+
+```js
+const csvStream = csv.format({ headers: [ 'header2', 'header1' ] });
+
+csvStream
+    .pipe(process.stdout)
+    .on('end', process.exit);
+
+csvStream.write({ header1: 'value1a', header2: 'value1b' });
+csvStream.write({ header1: 'value2a', header2: 'value2b' });
+csvStream.write({ header1: 'value3a', header2: 'value3b' });
+csvStream.write({ header1: 'value4a', header2: 'value4b' });
+csvStream.end();
+
+```
+
+Expected Output: 
+```
+header2,header1
+value1b,value1a
+value2b,value2a
+value3b,value3a
+value4b,value4a
+```
+
+<a name="headers-provided-object-remove-column"></a>
+[`examples/formatting/headers_provided_object_remove_column.example.js`](../examples/formatting/headers_provided_object_remove_column.example.js)
+
+In this example the one of the columns is removed.
+
+```js
+const csvStream = csv.format({ headers: [ 'header2' ] });
+
+csvStream
+    .pipe(process.stdout)
+    .on('end', process.exit);
+
+csvStream.write({ header1: 'value1a', header2: 'value1b' });
+csvStream.write({ header1: 'value2a', header2: 'value2b' });
+csvStream.write({ header1: 'value3a', header2: 'value3b' });
+csvStream.write({ header1: 'value4a', header2: 'value4b' });
+csvStream.end();
+```
+
+Expected Output: 
+```
+header2
+value1b
+value2b
+value3b
+value4b
+```
+
 <a name="examples-quote-columns"></a>
@@ -338,0 +539,0 @@ ### `quoteColumns`

History.md

@@ -0,1 +1,5 @@
+# v3.3.0
+
+* [FIXED] First row of CSV is removed when headers array is provided [#252](https://github.com/C2FO/fast-csv/issues/252)
+
 # v3.2.0
@@ -2,0 +6,0 @@

package.json

 {
   "name": "fast-csv",
-  "version": "3.2.0",
+  "version": "3.3.0",
   "description": "CSV parser and writer",
@@ -5,0 +5,0 @@ "main": "./build/src/index.js",

src/formatter/formatter/RowFormatter.ts

@@ -1,2 +0,2 @@
-import { isFunction } from 'lodash';
+import { isFunction, isEqual } from 'lodash';
 import { FormatterOptions } from '../FormatterOptions';
@@ -60,3 +60,3 @@ import FieldFormatter from './FieldFormatter';
 
-    private parsedHeaders: boolean;
+    private shouldWriteHeaders: boolean;
 
@@ -72,6 +72,7 @@ private hasWrittenHeaders: boolean;
         this._rowTransform = null;
+
         this.headers = formatterOptions.headers;
-        this.parsedHeaders = formatterOptions.hasProvidedHeaders && Array.isArray(formatterOptions.headers);
-        this.hasWrittenHeaders = !formatterOptions.hasProvidedHeaders;
-        if (this.parsedHeaders && this.headers !== null) {
+        this.shouldWriteHeaders = formatterOptions.shouldWriteHeaders;
+        this.hasWrittenHeaders = false;
+        if (this.headers !== null) {
             this.fieldFormatter.headers = this.headers;
@@ -102,4 +103,5 @@ }
                 const { shouldFormatColumns, headers } = this.checkHeaders(transformedRow);
-                if (headers) {
+                if (this.shouldWriteHeaders && headers && !this.hasWrittenHeaders) {
                     rows.push(this.formatColumns(headers, true));
+                    this.hasWrittenHeaders = true;
                 }
@@ -118,26 +120,36 @@ if (shouldFormatColumns) {
     private checkHeaders(row: Row): { headers?: string[] | null; shouldFormatColumns: boolean } {
-        if (!this.parsedHeaders) {
-            this.parsedHeaders = true;
-            this.headers = RowFormatter.gatherHeaders(row);
-            this.fieldFormatter.headers = this.headers;
+        if (this.headers) {
+            // either the headers were provided by the user or we have already gathered them.
+            return { shouldFormatColumns: true, headers: this.headers };
         }
-        if (this.hasWrittenHeaders) {
+
+        const headers = RowFormatter.gatherHeaders(row);
+        this.headers = headers;
+        this.fieldFormatter.headers = headers;
+        if (!this.shouldWriteHeaders) {
+            // if we are not supposed to write the headers then
+            // alwyas format the columns
             return { shouldFormatColumns: true, headers: null };
         }
-        this.hasWrittenHeaders = true;
-        const shouldFormatColumns = RowFormatter.isHashArray(row) || !Array.isArray(row);
-        return { shouldFormatColumns, headers: this.headers };
+        // if the row is equal to headers dont format
+        return { shouldFormatColumns: !isEqual(headers, row), headers };
     }
 
     private gatherColumns(row: Row): string[] {
+        if (this.headers === null) {
+            throw new Error('Headers is currently null');
+        }
         if (!Array.isArray(row)) {
-            if (this.headers === null) {
-                throw new Error('Headers is currently null');
-            }
             return this.headers.map((header): string => row[header]);
         }
         if (RowFormatter.isHashArray(row)) {
-            return row.map((col): string => col[1]);
+            return this.headers.map((header, i): string => {
+                const col = row[i];
+                if (col) {
+                    return col[1];
+                }
+                return '';
+            });
         }
-        return row;
+        return this.headers.map((header, i): string => row[i]);
     }
@@ -144,0 +156,0 @@

src/formatter/FormatterOptions.ts

@@ -43,3 +43,3 @@ import { RowTransformFunction } from './types';
 
-    public readonly hasProvidedHeaders: boolean;
+    public readonly shouldWriteHeaders: boolean;
 
@@ -58,3 +58,3 @@ public readonly escapedQuote: string;
         }
-        this.hasProvidedHeaders = !!this.headers;
+        this.shouldWriteHeaders = !!this.headers;
         this.headers = Array.isArray(this.headers) ? this.headers : null;
@@ -61,0 +61,0 @@ this.escapedQuote = `${this.escape}${this.quote}`;

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Improved metrics

Lines of code

2799

increased by0.72%

Worsened metrics

Total package byte prevSize

258042

decreased by-0.65%

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