breadth-filter


Apply a deep object filter via breadth traversal. It allows replacing values, including retargeting objects and arrays and even detecting circular references to allow the user to decide how to handle the circle. Note that the filter will _not_ descend _into_ circular objects but will only _reach_ them.

Install

``sh
npm install breadth-filter
`

Example

`js
const breadthFilter = require('breadth-filter')

const data = {
user: {
name: 'someone',
password: 'THIS SHOULD BE SECRET!!'
}
}

function onValue (value, key, path) {
if (key === 'password') {
console.log('redacted field at', path.join('.'))
return '[redacted]'
}
return value
}

// build a new filtered object...

const filtered = breadthFilter(data, {
onValue
})

// or, mutate in-place and break cycles...

breadthFilter(data, {
onValue,
onObject (value, key, path, isNew) {
return isNew ? value : '[Circular]'
},
onArray (value, key, path, isNew) {
return isNew ? value : '[Circular]'
}
})
`

Options

$3

This function handles primitive value types such as numbers or strings. It can be used to filter things like sensitive data such as passwords or credit card numbers.

Arguments:

* value - any
The encountered value to filter.
* key - string | number
The property key of the encountered value, at the current depth level. Will be null when encountering the root object.
* path - array
Any array of all property keys leading from the root to this encountered value.

$3

This handles encountered objects. It can be used to filter entire objects out of the result, by returning undefined, it can enable in-place mutation by return the value directly, and the isNew property can be used to identify and break out of circular references, replacing them with something else such as '[Circular]'.

Arguments:

* value - any
The encountered value to filter.
* key - string | number
The property key of the encountered value, at the current depth level. Will be null when encountering the root object.
* path - array
Any array of all property keys leading from the root to this encountered value.
* isNew - boolean
Indicates if this is the first time encountering this value, a false value indicates a circular reference.

$3

This handles encountered arrays. It can be used to filter entire arrays out of the result, by returning undefined, it can enable in-place mutation by return the value directly, and the isNew property can be used to identify and break out of circular references, replacing them with something else such as '[Circular]'.

Arguments:

* value - any
The encountered value to filter.
* key - string | number
The property key of the encountered value, at the current depth level. Will be null when encountering the root object.
* path - array
Any array of all property keys leading from the root to this encountered value.
* isNew` - boolean
Indicates if this is the first time encountering this value, a false value indicates a circular reference.

---

$3

#### Licensed under MIT License

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

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