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Description

Get the value of a property or a default value if the object does not have the given property. If no default value is given, null is returned.

Note
This function is not supported in Spark pipelines.

Syntax

object.get(field, [defaultValue])

Example

Expression: $.get("Id")

Result: Returns the value of the "Id" property or null if the object does not have the property.

Expression: $.get("Id", 123)

Result: Returns the value of the "Id" property or the number "123" if the object does not have the property.

...

Description

Find the value for the given property name. If the property does not exist, the function returns the default value (if given); otherwise, null is returned. If the value is a populated list, then the function returns the first value in the list; otherwise, it returns the default value if present or null.

Syntax

object.getFirst(propertyName, defaultValue)

Example

Expression: $.getFirst("test")

Where $test is the string "abc123"

Result: abc123

Expression: $.getFirst("test")

Where $test is a list consisting of [5, 10, 15, 20]

Result: 5

hasOwnProperty

Description

Indicates whether the object has the specified property.

The in operator and get method can be used as a shorthand to test if an object has a property or get the value of a property with a default if it does not exist.

Note

This argument is treated as a JSON-Path JSONPath instead of a plain property name and returns false if the property exists but the value is null. Most expressions should work as expected if the object is not a qualified path. If your expression passes a JSON-Path JSONPath or if the property value is null, use the hasPath method instead.

For example, if we use this object method to look up a property in an object, then we would have the following expression:

$.map.hasOwnProperty("route")

Where the property "route" is the target property in the object $.map.

Using this object method to find a path does not work as might be expected. For example:

$.hasOwnProperty("map.route")

Where map.route is a path and not a property.

In this case, we recommend you use the hasPath() method.

Syntax

Code Block
object.hasOwnProperty(field)

Example

Expression: $.hasOwnProperty("Id")

Result: Returns true if the object has the key "Id"

Expression: To create a ternary conditional expression:

$.hasOwnProperty('query') ? $query : 'not present in input'

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Description

Indicates whether the object has the specified property. This method is recommended when working with JSON-PathJSONPath, especially when looking for fields nested deep within the object.

Info
This expression is useful since, if you use Instead of chaining multiple sub-expressions using the hasOwnProperty method , you have to construct complex sub-expressions to check if the field existsto validate the subpath at each node of the JSONPath, you can call hasPath only once to do the same validation. You must provide the JSONPath to the property.

Syntax

Paste code macro
object.hasPath(fieldJSONPath.to.property)

Example

Expression: $.hasPath("Id")

Result: Returns true if the object has the key "Id"

Example JSON Object:

Paste code macro

language	json
title	JSON Example

{
  "Name":"previewdata.json",
  "Type":"File",
  "Size (in bytes)":"4",
  "Owner":null,
  "Update date":"2019-10-06T16:50:58.000Z",
  "Editor": {
    "EditorName": "John Doe",
    "Dept": "Marketing"
  }
  "Creation date":"unknown",
  "Permissions":"unknown"
}

Expression: $.hasPath("Type")

Result: Returns True

since

because the object "Type" has a specified value.

Expression: $.hasPath($.Editor.EditorName)

Result: Returns True because "EditorName" has a specified value.

Expression: $.hasPath("Owner")

Result: Returns False since even though the object has the key "Owner", it is null.

Expression: $.hasPath("Region")

Result: Returns False since the object does not have "Region".

isEmpty

Description

Returns true if the given object has no properties.

Note
This function is not supported in Spark pipelines.

Syntax

Code Block
object.isEmpty()

Example

Expression: {}.isEmpty()

Result: Returns true.

Expression: { foo: 1 }.isEmpty()

Result: Returns false.

...

Description

Create a new object that retains some properties from the original as specified by the given callback.

Syntax

Code Block
object.filter(callback)

callback - A function that takes three arguments (property-value, property-name, input-object) and returns true if the property should be included in the returned object or false if it should be left out.

Example

Expression: $.filter((value, key) => key.startsWith("new"))

Input:

Code Block
{ "key1": "abc", "key2": "xyz", "newField1": "foo", "newField2": "bar" }

Result:

Code Block
{ "newField1": "foo", "newField2": "bar" }

keys

Description

Returns an array of strings that represent all the enumerable properties of the given object. The ordering of the properties is the same as that given by looping over the properties of the object manually. See also values, entries.

Syntax

Code Block
property.keys()

Example

Input:

Code Block
let user = { name: "John", age: 30 }

Expression: $user.keys()
Result: [name, age]

...

Expand

title	Extend Method: Converting an array into an object

A JSON Array of objects with unique/non-overlapping keys can be converted to an object using the extend object method along with a Spread Operator. The extend object method does so by creating objects dynamically from other objects passed in as arguments, the spread operator will have to be used to indicate that the elements of the array should be treated as the arguments to the function. The expression to be used is:

Paste code macro

title	Expression using extend method to convert an array into an object

{}extend(...$<Array_name>)

1. Input the array into Mapper Snap (this can be done using a JSON Generator Snap). For this example, the following array will be used:

Paste code macro

language	json
title	JSON Array

{
 "myArray": [
   {
     "Header1": {
       "a": 11,
       "b": 21,
       "c": 31
     }
   },
   {
     "Header2": {
       "a": 12,
       "b": 22,
       "c": 32
     }
   },
   {
     "Header3": {
       "a": 13,
       "b": 23,
       "c": 33
     }
   }
 ]
}

2. The Mapper Snap must be configured as shown below. Notice the Expression and Target path fields.

3. When executed, the output will be an object.

Note
The array should have unique keys for this method to work, if they overlap then the last element of the array will be converted.

Versions Compared

Old Version 50

New Version 51

Key

hasOwnProperty

isEmpty

keys

1. Input the array into Mapper Snap (this can be done using a JSON Generator Snap). For this example, the following array will be used:

2. The Mapper Snap must be configured as shown below. Notice the Expression and Target path fields.

3. When executed, the output will be an object.