@giorgi-g/csv-parser/README.md

CSV parser for migrations with Sequelizer

## CSV PARSER ON STEROIDS
__CSV files parser on TypeScript with Sequelizer. For easier migration.__
___
### Install npm modules
```shell
npm install
```

### Then configure a database according to the [.env.example](.env.example) file
#### In [config.ts](config.ts) you will also see sample default values... 
___

### We can define different options upon reading a file e.g:
```javascript
interface CSVParserOptions {
    mapKeyIndexes?: number[];
    mapKeySeparator?: string;
    classPath?: string;
    classObjectGetterName?: string;
    delimiter?: string;
    rootDir?: string;
    rootEnv?: string;
    fileExtension?: string;
   mergeMapKeyValues?: boolean;
}
```
___
1. ***mapKeyIndexes*** 
   * After reading a file a `Map<any|number, any>` is generated by default it has numeric index as a key, but we can assign a key generated by the properties.
   * If we want records to have a custom key from [CSV](files/sample_profiles_dev01.csv) file e.g: **email** we can set `mapKeyIndexes: [3]` where **3** is the index in [CSV](files/sample_profiles_dev01.csv) for **email**.
   * We can also have combined key e.g: `[0, 3]` which will give us `${ID}-${EMAIL}`
   * **Note**: the keys are separated by the **Dash** symbol if you want to override the default you can change the value of `mapKeySeparator` key.

2. ***classPath*** **&&** ***classObjectGetterName***
    * After parsing the data from CSV you can cast it to a certain **Class** which by default can be created inside [entities'](src/entities) folder. e.g: `{ classPath: '../entities/Profile' }`
    * If you want value of the map to be some certain property or getter inside the Class you can provide a value for **classObjectGetterName** e.g: `{ classObjectGetterName: 'profile' }` which is the [profile](src/entities/Profile.ts) property inside the class
3. ***delimiter*** 
   * As a delimiter your CSV file can contain **[`comma: ,`]** symbol if that is not the default for your CSV you can provide a different value defined inside.
4. ***mergeMapKeyValues***
   * While setting a map to the key if you want to receive the same key values in an array make this value true
___


### Example:
```typescript
const fileName = "sample_profiles"; // file name inside /files/FILE_NAME.csv

 const options: CSVParserOptions = {
   classPath: '../entities/Profile', // Class name if you want to cast result into a class
   classObjectGetterName: 'profile', // Name of the property inside the Class which will be the value inside the Map
   mapKeyIndexes: [3] // Email as a key of the Map
 };

 // Initialize the parser with properties
 const csvParser = new CSVParser(
     fileName,
     options,
 );

 // Read the data inside the parser
 csvParser.Read().then((data) => {
   data.forEach((profile) => {
       console.log('>>> profile', profile);
   })
 });





const connection = dbConnection("profile", 100, 0).then((response) => {
   console.log('>>> response from db:', response);
}).catch((error) => {
   console.log('>>> error: ', error);
});


dbConnection = async (schema?: string, limit: number = 0, offset: number = 0) => {
   const DB = Sequelizer(schema);
   return DB.query(`SELECT uuid, brand_id FROM 
                profile.profiles
            WHERE brand_id IS NOT NULL
            ORDER BY uuid DESC LIMIT ${limit} OFFSET ${offset}`,
           {
              type: QueryTypes.SELECT,
              logging: false,
           });
}
```