mirror of
https://github.com/gradle/gradle-build-action.git
synced 2024-12-27 03:36:19 +08:00
248 lines
5.0 KiB
Markdown
248 lines
5.0 KiB
Markdown
traverse
|
|
========
|
|
|
|
Traverse and transform objects by visiting every node on a recursive walk.
|
|
|
|
examples
|
|
========
|
|
|
|
transform negative numbers in-place
|
|
-----------------------------------
|
|
|
|
negative.js
|
|
|
|
````javascript
|
|
var traverse = require('traverse');
|
|
var obj = [ 5, 6, -3, [ 7, 8, -2, 1 ], { f : 10, g : -13 } ];
|
|
|
|
traverse(obj).forEach(function (x) {
|
|
if (x < 0) this.update(x + 128);
|
|
});
|
|
|
|
console.dir(obj);
|
|
````
|
|
|
|
Output:
|
|
|
|
[ 5, 6, 125, [ 7, 8, 126, 1 ], { f: 10, g: 115 } ]
|
|
|
|
collect leaf nodes
|
|
------------------
|
|
|
|
leaves.js
|
|
|
|
````javascript
|
|
var traverse = require('traverse');
|
|
|
|
var obj = {
|
|
a : [1,2,3],
|
|
b : 4,
|
|
c : [5,6],
|
|
d : { e : [7,8], f : 9 },
|
|
};
|
|
|
|
var leaves = traverse(obj).reduce(function (acc, x) {
|
|
if (this.isLeaf) acc.push(x);
|
|
return acc;
|
|
}, []);
|
|
|
|
console.dir(leaves);
|
|
````
|
|
|
|
Output:
|
|
|
|
[ 1, 2, 3, 4, 5, 6, 7, 8, 9 ]
|
|
|
|
context
|
|
=======
|
|
|
|
Each method that takes a callback has a context (its `this` object) with these
|
|
attributes:
|
|
|
|
this.node
|
|
---------
|
|
|
|
The present node on the recursive walk
|
|
|
|
this.path
|
|
---------
|
|
|
|
An array of string keys from the root to the present node
|
|
|
|
this.parent
|
|
-----------
|
|
|
|
The context of the node's parent.
|
|
This is `undefined` for the root node.
|
|
|
|
this.key
|
|
--------
|
|
|
|
The name of the key of the present node in its parent.
|
|
This is `undefined` for the root node.
|
|
|
|
this.isRoot, this.notRoot
|
|
-------------------------
|
|
|
|
Whether the present node is the root node
|
|
|
|
this.isLeaf, this.notLeaf
|
|
-------------------------
|
|
|
|
Whether or not the present node is a leaf node (has no children)
|
|
|
|
this.level
|
|
----------
|
|
|
|
Depth of the node within the traversal
|
|
|
|
this.circular
|
|
-------------
|
|
|
|
If the node equals one of its parents, the `circular` attribute is set to the
|
|
context of that parent and the traversal progresses no deeper.
|
|
|
|
this.update(value)
|
|
------------------
|
|
|
|
Set a new value for the present node.
|
|
|
|
this.remove()
|
|
-------------
|
|
|
|
Remove the current element from the output. If the node is in an Array it will
|
|
be spliced off. Otherwise it will be deleted from its parent.
|
|
|
|
this.delete()
|
|
-------------
|
|
|
|
Delete the current element from its parent in the output. Calls `delete` even on
|
|
Arrays.
|
|
|
|
this.before(fn)
|
|
---------------
|
|
|
|
Call this function before any of the children are traversed.
|
|
|
|
this.after(fn)
|
|
--------------
|
|
|
|
Call this function after any of the children are traversed.
|
|
|
|
this.pre(fn)
|
|
------------
|
|
|
|
Call this function before each of the children are traversed.
|
|
|
|
this.post(fn)
|
|
-------------
|
|
|
|
Call this function after each of the children are traversed.
|
|
|
|
methods
|
|
=======
|
|
|
|
.map(fn)
|
|
--------
|
|
|
|
Execute `fn` for each node in the object and return a new object with the
|
|
results of the walk. To update nodes in the result use `this.update(value)`.
|
|
|
|
.forEach(fn)
|
|
------------
|
|
|
|
Execute `fn` for each node in the object but unlike `.map()`, when
|
|
`this.update()` is called it updates the object in-place.
|
|
|
|
.reduce(fn, acc)
|
|
----------------
|
|
|
|
For each node in the object, perform a
|
|
[left-fold](http://en.wikipedia.org/wiki/Fold_(higher-order_function))
|
|
with the return value of `fn(acc, node)`.
|
|
|
|
If `acc` isn't specified, `acc` is set to the root object for the first step
|
|
and the root element is skipped.
|
|
|
|
.deepEqual(obj)
|
|
---------------
|
|
|
|
Returns a boolean, whether the instance value is equal to the supplied object
|
|
along a deep traversal using some opinionated choices.
|
|
|
|
Some notes:
|
|
|
|
* RegExps are equal if their .toString()s match, but not functions since
|
|
functions can close over different variables.
|
|
|
|
* Date instances are compared using `.getTime()` just like `assert.deepEqual()`.
|
|
|
|
* Circular references must refer to the same paths within the data structure for
|
|
both objects. For instance, in this snippet:
|
|
|
|
````javascript
|
|
var a = [1];
|
|
a.push(a); // a = [ 1, *a ]
|
|
|
|
var b = [1];
|
|
b.push(a); // b = [ 1, [ 1, *a ] ]
|
|
````
|
|
|
|
`a` is not the same as `b` since even though the expansion is the same, the
|
|
circular references in each refer to different paths into the data structure.
|
|
|
|
However, in:
|
|
|
|
````javascript
|
|
var c = [1];
|
|
c.push(c); // c = [ 1, *c ];
|
|
````
|
|
|
|
`c` is equal to `a` in a `deepEqual()` because they have the same terminal node
|
|
structure.
|
|
|
|
* Arguments objects are not arrays and neither are they the same as regular
|
|
objects.
|
|
|
|
* Instances created with `new` of String, Boolean, and Number types are never
|
|
equal to the native versions.
|
|
|
|
.paths()
|
|
--------
|
|
|
|
Return an `Array` of every possible non-cyclic path in the object.
|
|
Paths are `Array`s of string keys.
|
|
|
|
.nodes()
|
|
--------
|
|
|
|
Return an `Array` of every node in the object.
|
|
|
|
.clone()
|
|
--------
|
|
|
|
Create a deep clone of the object.
|
|
|
|
installation
|
|
============
|
|
|
|
Using npm:
|
|
npm install traverse
|
|
|
|
Or check out the repository and link your development copy:
|
|
git clone http://github.com/substack/js-traverse.git
|
|
cd js-traverse
|
|
npm link .
|
|
|
|
You can test traverse with "expresso":http://github.com/visionmedia/expresso
|
|
(`npm install expresso`):
|
|
js-traverse $ expresso
|
|
|
|
100% wahoo, your stuff is not broken!
|
|
|
|
hash transforms
|
|
===============
|
|
|
|
This library formerly had a hash transformation component. It has been
|
|
[moved to the hashish package](https://github.com/substack/node-hashish).
|