Easy table

Simple and nice utility for rendering text tables with javascript.

Usage

var Table = require('easy-table');

var data = [
    { id: 123123, desc: 'Something awesome', price: 1000.00 },
    { id: 245452, desc: 'Very interesting book', price: 11.45},
    { id: 232323, desc: 'Yet another product', price: 555.55 }
]

var t = new Table;

data.forEach(function (product) {
    t.cell('Product Id', product.id);
    t.cell('Description', product.desc);
    t.cell('Price, USD', product.price, Table.Number(2));
    t.newRow();
});

console.log(t.toString());

The script above will render:

Product Id  Description            Price, USD
----------  ---------------------  ----------
123123      Something awesome         1000.00
245452      Very interesting book       11.45
232323      Yet another product        555.55

t.printTransposed() yields

Product Id  : 245452                : 232323              : 123123
Description : Very interesting book : Yet another product : Something awesome
Price, USD  : 11.45                 : 555.55              : 1000.00

Finally t.print() shows just the rows you pushed and nothing more

245452  Very interesting book    11.45
232323  Yet another product     555.55
123123  Something awesome      1000.00

How it works

The full signature of .cell() method is:

t.cell(column, value, printer, width)

By default column's width is ajusted to fit the longest value, but if specified explicitly it is fixed and any non-fitting cell is truncated.

Cell's value rendering occures in two phases. At the first phase printer function is called to get minimal width required to fit cell correctly, at the second phase printer function is called to get actual string to render with additional width parameter supplied.

// Example: Coloring too big numbers in red

function markTooBigs (val, width) {
    if (width == null) return Table.string(val)
    return val > 100
        ? '\033[31m' + String(val) + '\033[39m'
        : Table.string(val)
}
...
t.cell('foo', 300, markTooBigs)

Table.printArray(), Table.printObject()

Often you just want to print an array or a simple key-value map. Table.printArray() and Table.printObject() help to instantiate and fill a table for such use cases.

var array = [
    {foo: 'foo1', bar: 'bar1'},
    {foo: 'foo2', bar: 'bar2'}
]

console.log(Table.printArray(array))

yields

foo   bar
----  ----
foo1  bar1
foo2  bar2

we can pass options to override defaut behaviour

Table.printArray(array, {
    bar: {
        name: 'Long field name',
        printer: Table.padLeft
    }
})

foo   Long field name
----  ---------------
foo1             bar1
foo2             bar2

or have a full control over rendering

Table.printArray(array, function (obj, cell) {
    cell('foo', obj.foo)
    cell('field', obj.bar)
}, function (table) {
    return table.print()
})

Table.printObj() works in the same manner

var obj = {
    foo: 'foo',
    bar: 'bar'
}

Table.printObj(obj)

yields

foo : foo
bar : bar

Sorting

You can sort a table by calling .sort(), and optionally passing in a list of column names to sort on (by default uses all columns), or a custom comparator function. It is also possible to specify the sort order. For example:

t.sort(['Price, USD|des']) // will sort in descending order
t.sort(['Price, USD|asc']) // will sort in ascending order
t.sort(['Price, USD']) // sorts in ascending order by default

Totaling

Easy table can help you to calculate and render totals:

t.total('Price, USD', function accumulator (sum, val, index, length) {
    sum = sum || 0
    sum += val
    return index + 1 == length
        ? sum / length
        : sum
}, function print (val, width) {
    var s = 'Avg: ' + Table.Number(2)
    return width == null
        ? s
        : Table.padLeft(s, width)
})

yields

Product Id  Description            Price, USD
----------  ---------------------  -----------
245452      Very interesting book        11.45
232323      Yet another product         555.55
123123      Something awesome          1000.00
----------  ---------------------  -----------
                                   Avg: 522.33

total() function also accepts printer via printer property of accumulator, so it is possible to create reusable aggregations like:

var priceAvg = // some accumulator
priceAvg.printer = // some printer
...
t.total('Price', 300.50, priceAvg)

Installation

Just install from the npm repository with:

$ npm install easy-table

Misc

Easy table now has kind of stable api and exposes many of it's internals. But in any case it's better to specify strict version numbers in your modules especially if you use methods or properties not covered by this readme.

License

(The MIT License)

Copyright (c) 2012 Eldar Gabdullin eldargab@gmail.com

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.