Migration.guide.md

Migration Guides

From v.3.x.x - v.4.x.x

Walk version 4 provides support for all javascript primitive types including null and undefined. Untill version 3, callback returns null if value should be ignored. Walk v.4 provides argument constant IGNORE. Return it if need to ignore. Returning of null and undefined will be treated as standard values.

//v.3
function someKeyCallback ({value, key, breadcrumbs }) {
            if ( value == 'something' )   return null   // will cancel 
            return value
    }

// v.4
function someKeyCallback ({value, key, breadcrumbs, IGNORE }) {
            if ( value == 'something' )   return IGNORE   // will cancel 
            return value
    }

That's all changes needed to move from v.3.x.x to v.4.x.x.

From v.2.x.x. - v.3.x.x

Major changes are related to moving from multiple arguments to named arguments.

const someData = { a: 12, b: ['one', 'two'] }
// old:
const result = walk ( someData )
// new:
const result = walk ({ data: someData })

Calling walk with keyCallback

// old
// - first version:
const result = walk ( someData, keyCallbackFn ) 
// - second version:
const result = walk ( someData, [keyCallbackFn,null])

// new:
const result = walk ({ data:someData, keyCallback: keyCallbackFn })

Calling walk with both callbacks:

//old:
const result = walk ( someData, [keyCallbackFn, objectCallbackFn])
// new:
const result = walk ({ 
                          data:someData
                        , keyCallback:keyCallbackFn
                        , objectCallback:objectCallbackFn 
                    })

Definition for objectCallbacks:

// old
function callback ( obj, key, breadcrumbs ) {
        //... some actions
    }

// new
function callback ({ value, key, breadcrumbs }) {
        //... some actions
    }

Definition for keyCallbacks:

// old
function callback (value,key,breadcrumbs) {
         //... some actions
    }


function callback ({value,key,breadcrumbs}) {
         //... some actions
    }