Export result set to CSV file #81

src/lib/csv.js

@@ -0,0 +1,113 @@
+import Papa from 'papaparse'
+
+const hintsByCode = {
+  MissingQuotes: 'Edit your CSV so that the field has a closing quote char.',
+  TooFewFields: 'Add fields or try another delimiter.',
+  TooManyFields: 'Edit your CSV or try another delimiter.'
+}
+
+export default {
+  getResult (source) {
+    const result = {
+      columns: []
+    }
+    const values = {}
+    if (source.meta.fields) {
+      source.meta.fields.forEach(col => {
+        const colName = col.trim()
+        result.columns.push(colName)
+        values[colName] = source.data.map(row => {
+          let value = row[col]
+          if (value instanceof Date) {
+            value = value.toISOString()
+          }
+          return value
+        })
+      })
+    } else {
+      for (let i = 0; i <= source.data[0].length - 1; i++) {
+        const colName = `col${i + 1}`
+        result.columns.push(colName)
+        values[colName] = source.data.map(row => {
+          let value = row[i]
+          if (value instanceof Date) {
+            value = value.toISOString()
+          }
+          return value
+        })
+      }
+    }
+
+    result.values = values
+    return result
+  },
+
+  prepareForExport (resultSet) {
+    const columns = resultSet.columns
+    const rowCount = resultSet.values[columns[0]].length
+    const result = {
+      fields: columns,
+      data: []
+    }
+
+    for (let rowNumber = 0; rowNumber < rowCount; rowNumber++) {
+      result.data.push(columns.map(column => resultSet.values[column][rowNumber]))
+    }
+
+    return result
+  },
+
+  parse (file, config = {}) {
+    return new Promise((resolve, reject) => {
+      const defaultConfig = {
+        delimiter: '', // auto-detect
+        newline: '', // auto-detect
+        quoteChar: '"',
+        escapeChar: '"',
+        header: false,
+        transformHeader: undefined,
+        dynamicTyping: true,
+        preview: 0,
+        encoding: 'UTF-8',
+        worker: true,
+        comments: false,
+        step: undefined,
+        complete: results => {
+          const res = {
+            data: this.getResult(results),
+            delimiter: results.meta.delimiter,
+            hasErrors: false,
+            rowCount: results.data.length
+          }
+          res.messages = results.errors.map(msg => {
+            msg.type = msg.code === 'UndetectableDelimiter' ? 'info' : 'error'
+            if (msg.type === 'error') res.hasErrors = true
+            msg.hint = hintsByCode[msg.code]
+            return msg
+          })
+          resolve(res)
+        },
+        error: (error, file) => {
+          reject(error)
+        },
+        download: false,
+        downloadRequestHeaders: undefined,
+        downloadRequestBody: undefined,
+        skipEmptyLines: 'greedy',
+        chunk: undefined,
+        chunkSize: undefined,
+        fastMode: undefined,
+        beforeFirstChunk: undefined,
+        withCredentials: undefined,
+        transform: undefined,
+        delimitersToGuess: [',', '\t', '|', ';', Papa.RECORD_SEP, Papa.UNIT_SEP]
+      }
+
+      Papa.parse(file, { ...defaultConfig, ...config })
+    })
+  },
+
+  serialize (resultSet) {
+    return Papa.unparse(this.prepareForExport(resultSet))
+  }
+}