go-tablewriter

This module implements a writer for table data, which can be output as CSV or Text.

Example:

package main

import (
    tablewriter "github.com/djthorpe/go-tablewriter"

)

func main() {
  table := []TableData{
    {A: "hello", B: "world"},
  }
  writer := tablewriter.New(os.Stdout)
  writer.Write(table, tablewriter.OptHeader())
}

The Write function expects a single struct or a slice of structs as the first argument. Each struct represents a row in the table. The struct fields (including any which are embedded) are used as columns in the table.

Table Options

The following options can be used to customize the output:

• tablewriter.OptHeader(): Output the header row.
• tablewriter.OptTag("json"): Set the struct field tag which is used to set options, default is "json".
• tablewriter.OptFieldDelim('|'): Set the field delimiter, default is ',' for CSV and '|' for Text.
• tablewriter.OptOutputCSV(): Output as CSV.
• tablewriter.OptOutputText(): Output as Text.
• tablewriter.OptNull("<nil>"): Set how the nil value is represented in the output, defaults to <nil>.

Struct Tags

Tags on struct fields can determine how the field is output. The json tag is used by default.

• json:"-": Skip the field.
• json:"Name": Set the column header to "Name".
• json:",omitdefault": If all values in the table are zero-valued, skip output of the column (TODO)
• json:",wrap": Field is wrapped to the width of the column.
• json:",right": Field is right-aligned in the column.
• json:",width:20": Suggested column width is 20 characters

Customize Field Output

You can implement the following interface on any field to customize how it is output:

type Marshaller interface {
  Marshal() ([]byte, error)
}

By default, strings and time.Time types are output as-is and other values are marshalled using the encoding/json package.

Contribution and License

See the LICENSE file for license rights and limitations, currently Apache. Pull requests and issues are welcome.

Changelog

• v0.0.1 (May 2024) Initial version
• v0.0.2 (May 2024) Documentation updates
• v0.0.4 (May 2024) Added text wrapping for text output
• v0.0.5 (May 2024) Exposing options for customizing the output in the struct tags

Future versions will include more options for customizing the output:

• Setting the width of the table based on terminal width
• Estimating sizing the width of fields for the text package
• Omitting columns based on zero-value
• Adding JSON and SQL output
• Outputing fields with ANSI color codes
• Adding a separate tag for tablewriter options instead of using json