README.md

@teamhive/csv-processor

csv-processor is a package that simplifies reading and transforming CSV data into other formats through TypeDI services. The typical usecase for the package would be converting a CSV file into individual SQL insert statements. This package handles all of the file I/O as well as recognizing line breaks within single or double quote

Usage

To install the package, run:

npm i @teamhive/csv-processor

The package itself defines two main export ProcessInput and ProcessOutput. Both classes are typedi services and should be constructed as typedi dependencies.

ProcessOuput

This service opens up a file to write to and line-by-line writes the input provided by the addLine(columns: string[], values: string[]) function. To open up the output file, call

processOutput.initialize(filePath: string, transform: TransformInput)

This will open the file and wait for calls to addLine().

Once all lines have been written to the output, close() should be called.

TransformOutput

TransformOuput is an interface for creating a transform that converts the input of addLine into a string that will be printed to the output file.

export interface TransformOutput {
    transformOutput(columns: string[], vals: string[]): string;
}

When using ProcessOutput, an implementation of TransformOutput must be passed to the initialize function. A transform is required for output since the arrays must be formatted as a string.

ProcessInput

ProcessInput is a TypeDi service that reads in a csv file and passses the read input to a ProcessOutput instance. TypeDi handles the injection of contructed ProcessOuput instance.

To use ProcessInput, simply call the processFile(filePath: string, transform?: TransformInput, useSingleQuotes: boolean) function on an instance of ProcessInput. For input, the transform is not necessary. If useSingleQuotes is true, new lines and commas within matched single quotes will not be used as delimeters. Otherwise, it uses double quotes as a delimeter.

TransformInput

TransformInput is an interface for creating a transform that converts the read input from the csv file before it is passed to addLine.

export interface TransformOutput {
    transformOutput(columns: string[], vals: string[]): string;
}

Example

export class AppService {

    constructor(
        private readonly errorHandler: ErrorHandler,
        private readonly processOutput: ProcessOutput,
        private readonly processInput: ProcessInput,
        private readonly transformInput: TransformAddDescriptionHtml,
        private readonly transformOuput: TransformWrapLink
    ) { }

    async run() {
        try {
            const startTime = Date.now();
            this.errorHandler.captureBreadcrumb({ message: 'Running TypeDi Seed...' });

            const inputPath = path.join(__dirname, '../../', config.get<string>('path.input'));
            const outputPath = path.join(__dirname, '../../', config.get<string>('path.output'));
            await this.processOutput.initialize(outputPath, this.transformOuput);
            await this.processInput.processFile(inputPath, this.transformInput);
            await this.processOutput.close();

            this.errorHandler.captureBreadcrumb({ message: `Finished TypeDi seeds in ${Date.now() - startTime} ms` });
            this.exit();
        }
        catch (error) {
            // await to guarantee the error gets captured before the process exits
            await this.errorHandler.captureException(error);
            this.exit();
        }
    }

    private exit(): void {
        // any preexit tasks

        process.exit();
    }
}

Distribution

npm pack
npm version (major|minor|patch)
npm publish

Note: This will also automatically push changes and tags post-publish