slice-of-life

Helps to convert "per page" and "page number" to skip/take values

npm install slice-of-life
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Helper functions to create paginated REST APIs in node.js. Took some ideas from the github api v3.

slice of life boat

I took the name from Dexter Morgan boat because I like the show and paginate is already used :)

Installation

npm install slice-of-life

The convert method

This is useful for cases when you want to ask the consumer just the page number and maybe the per page amount of objects, but you have to convert this information to the classical skip, take, limit.

var sliceOfLife = require('slice-of-life');

var pageData = sliceOfLife.convert({
  per_page: 100, //perPage also works
  page: 5
});

console.log(pageData);

// will print {skip: 500, limit: 100} as simple as that.

The convert middleware

There is also an express middleware to do the convert

var sliceOfLife = require('slice-of-life');

//setup
app.use(sliceOfLife.convertMiddleware({defaultPerPage: 100}));

//then in a route:

app.get('/customers', function (req, res) {
  console.log(req.pageData);
  //will print {skip: xx, limit: xx};
});

The Linker

SliceOfLife has also a linker class to create links to other pages.

var Linker = require('slice-of-life').Linker,
    linker = new Linker('http://awesome.com/products?per_page=$per_page&page=$page');

var links = linker.createLinks({
 per_page: 10,
 total: 100,
 page: 5
});

console.log(links);

/* It will return an object like this:
  {
    'first': 'http://awesome.com/products?per_page=30&page=10',
    'prev': 'http://awesome.com/products?per_page=10&page=0',
    'next': 'http://awesome.com/products?per_page=30&page=2',
    'last': 'http://awesome.com/products?per_page=30&page=10'
  }
*/

The create links method needs these options:

  • per_page: the amount of objects to retrieve in each page
  • total: the total amount of objects in the object set
  • page: the current page index (base 0)

linker.createLinksHeader

The createLinksHeader method of the linker does the same thing than createLinks but it returns an string with the Links header format.


var links = linker.createLinksHeader({
 per_page: 10,
 total: 100,
 page: 5
});

console.log(links);

/*
It will print something like:

<http://awesome.com/customers?per_page=10&page=0>; rel="first",
  <http://awesome.com/customers?per_page=10&page=1>; rel="prev",
  <http://awesome.com/customers?per_page=10&page=3>; rel="next",
  <http://awesome.com/customers?per_page=10&page=10>; rel="last"

(without line breaks)
*/

License

I know how hard and well-engineered this thing seems but I don't want to be billionary with this module, so this is MIT licensed :)

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