@loadingio/ldquery NPM

@loadingio/ldquery

lightweight DOM Helpers in Vanilla JS.

Installation

install via npm:

npm install @loadingio/ldquery

or, download it from github:

https://github.com/loadingio/ldquery/releases/latest/download/ldq.js
https://github.com/loadingio/ldquery/releases/latest/download/ldq.min.js

or use it directly via CDN:

https://cdn.jsdelivr.net/gh/loadingio/ldquery@v1.1.3/dist/ldq.js
https://cdn.jsdelivr.net/gh/loadingio/ldquery@v1.1.3/dist/ldq.min.js

in you html, include it directly with <script> tag:

<script src="https://cdn.jsdelivr.net/gh/loadingio/ldquery@v1.1.3/dist/ldq.min.js"></script>

Usage

ldquery provides following functions:

find(node, selector, index): shorthand for querySelector and querySelectorAll. return array when index is omitted.
index(node): index of node in childNodes of its parent.
child(node): children of node, in Array.
parent(node, selector, endNode): search parent(including node) for which matching the selector, until endNode is reached. return null if not found.
attr(node, name, value): get attribute "name" if value is omitted. set attribute if value is provided.
on(node, name, callback): addEventListener on event name.
remove(node): remove node from parent.
insertAfter(node, newNode, oldNode): insert newNode after oldNode under node.
fetch: fetch API helper.
xhr: XMLHttpRequest API helper.
json(data): handy function to convert things to object.
cls(o,p,n): handy function for setting classes.
- o: either object or value.
  - object: class name / on,off pair
  - value: true to toggle classes in p on, and classes in n off. vice versa.
- p: positive class list ( toggled when o is true )
- n: negative class list ( toggled when o is false ) invoke these functions with ld$, e.g.,
```
ld$.find(document.body, '.btn', 0) 
```

or ignore the first parameter if it's document:

ld$.find('.btn', 0)  /* equivalent to ld$.find(document, '.btn', 0) */

It also provides in wrapper style:

ld$(document.body).find('.btn', 0)

While it's not a good idea but you can pollute the native DOM for a more intuitive way to use these functions:

# in livescript syntax
HTMLElement.prototype <<< ld$obj.prototype

This could be enabled by remove the comment mark in corresponding line inside ldq.ls.

Fetch

ldquery wraps fetch api with promise-based error handling and some additional parameter.

ld$.fetch(<URL>, <RAWOPTION>, <LDQOPTION>)
  .then ->  ...
  .catch (e) -> # use e.data to get raw response from fetch

Common raw options:

method: HTTP method. e.g., "POST"
body: things to send to server. pass JSON by stringify it.
- ld$.fetch "url", {body: JSON.stringify({data: 1})}
headers: header hash. customize your own header here.

Common ldquery Options:

type: indicate the response data type. could be text or json.
json: json object to pass. shorthand for manually setting headers and stringify object.
- this: ld$.fetch("url", {}, {json: {data: 1}})
- is the same with this: ld$.fetch("url", {body: "{data: 1}", headers: {'Content-Type': 'application/json; charset=UTF-8'}})
params: shorthand for setting get params. expect an object with key/value pair. will convert it to querystring.
- this: `ld$.fetch("url", {}, {params: {qs: "some text"}}
- is the same with this: `ld$.fetch("url?qs=some%20text", {}, {})
timeout: elapsed time ( in milliseconds ) for a timeout error to be fired. default 40s
no-default-headers: default null. set this to true to bypass default headers in ld$.fetch.headers.

You can also config global headers by updating values in ld$.fetch.headers:

ld$.fetch.headers["X-CSRF-TOKEN"] = ...

XMLHttpRequest

While fetch is newer than XMLHttpRequest, for now XMLHttpRequest does better in handling progress information. Thus you can use ld$.xhr instead of ld$.fetch if such information is needed.

Using xhr is almost identical with using fetch:

ld$.xhr(<URL>, <RAWOPTION>, <LDQOPTION>)
  .then ->  ...
  .catch (e) -> # use e.data to get raw response from fetch

Yet it accepts one additional ldquery option:

progress({percent, val, len}): a callback function accepting progress information as an object
- percent: 0 ~ 1, 1 = finished.
- val: current progress.
- len: expected total progress.
- this function has no expected return value.

Error Handling

ld$.fetch doesn't depend on ldError, but it indeed returns ldError compatible errors, with following fields:

name: ldError
id: error code
code: http code. ( optional )
data: returned data
json: parsed json from returned data, if any ( optional )

When request failed, ld$.fetch will try to parse returned data as json, and check if there is a field "name" with value "ldError". If "ldError" name field exists, this object will be used directly to construct the Error object.

Compatibility

ldquery uses following modern web features:

fetch api - not support in IE, Older Edge ( <= 13). Use polyfill to support to IE >= 11
classList - not support well in IE. Use Polyfill to fix this.
Array.from - not supported in IE. Use Polyfill to fix this.