add new sql.js module and tests #27

src/sql.js

@@ -0,0 +1,79 @@
+import initSqlJs from 'sql.js/dist/sql-wasm.js'
+import dbUtils from '@/dbUtils'
+
+let SQL = null
+const sqlModuleReady = initSqlJs().then(sqlModule => { SQL = sqlModule })
+
+export default class Sql {
+  constructor () {
+    this.db = null
+  }
+
+  static build () {
+    return sqlModuleReady
+      .then(() => {
+        return new Sql()
+      })
+  }
+
+  createDb (buffer) {
+    if (this.db != null) this.db.close()
+    this.db = new SQL.Database(buffer)
+    return this.db
+  }
+
+  open (buffer) {
+    this.createDb(buffer && new Uint8Array(buffer))
+    return {
+      ready: true
+    }
+  }
+
+  exec (sql, params) {
+    if (this.db === null) {
+      this.createDb()
+    }
+    if (!sql) {
+      throw new Error('exec: Missing query string')
+    }
+    return this.db.exec(sql, params)
+  }
+
+  import (columns, values, progressCounterId, progressCallback, chunkSize = 1500) {
+    this.createDb()
+    this.db.exec(dbUtils.getCreateStatement(columns, values))
+    const chunks = dbUtils.generateChunks(values, chunkSize)
+    const chunksAmount = Math.ceil(values.length / chunkSize)
+    let count = 0
+    const insertStr = dbUtils.getInsertStmt(columns)
+    const insertStmt = this.db.prepare(insertStr)
+
+    progressCallback({ progress: 0, id: progressCounterId })
+    for (const chunk of chunks) {
+      this.db.exec('BEGIN')
+      for (const row of chunk) {
+        insertStmt.run(row)
+      }
+      this.db.exec('COMMIT')
+      count++
+      progressCallback({ progress: 100 * (count / chunksAmount), id: progressCounterId })
+    }
+
+    return {
+      finish: true
+    }
+  }
+
+  export () {
+    return this.db.export()
+  }
+
+  close () {
+    if (this.db) {
+      this.db.close()
+    }
+    return {
+      finished: true
+    }
+  }
+}