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Object Literals

...

In this Page

Table of Contents

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exclude	Additional Resources\|Related Links\|Related Information

Object Literals

Description

Object literals allow you to construct an object with a set of properties.

Object literals function similar to JavaScript object literals.

Within the object literal, the following variables are available:

this - A reference to the current object that can be used to reference previously defined properties.
__parent__ - A reference to the parent object when used within a nested object literal.
__root__ - A reference to the top-level object when used within a deeply nested object literal.

Syntax

An object literal is a comma-delimited list of zero or more pairs of property names and values surrounded by curly braces ({}), like so:

Code Block
{ property-name1 : value1, property-name2 : value2, ... property-nameN : valueN, }

The property name can be computed dynamically by enclosing an expression in square brackets ([]), like so:

Code Block
[expression] : value

The result of the expression will be converted into a string.

Example

Code Block

{
    "msg": "Hello, World!",
    /* Unlike JSON, property names do not need to be quoted */
    num: 123,
    /* Property names can be computed using an expression inside square brackets */
    [2 * 2]: "four",
    /* Other fields in this object can be referenced using the 'this' variable */
    ref: this.num + 7 /* sets 'ref' equal to 130 (123 + 7) */
}

...

This function is not supported in Spark pipelines.

The extend object method can also be used to convert an array of objects into an object. An example illustrating the same is described in the Example Use Cases section below.

Description

Returns a new object with the properties of the current one merged with the properties of the objects that were passed in. This is similar to http://underscorejs.org/#extend, but the extend object method returns a new object instead of modifying the given one.

Note

Syntax

Code Block
object.extend(target:data)

Example

Expression: $.extend({ newField1 : 'foo' }, { newField2 : 'bar' })

Input:

Code Block
{}

Result:

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

Note

When using the above expression in a Mapper ensure that the input stream is not empty else a null value error will be shown. If an empty document is to be created then use {} instead of $:

{}.extend({ newField1 : 'foo' },{ newField2 : 'bar' })

...

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.

...

getFirst

Description

Indicates whether Find the object has value for the specified given 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 function is not supported in Spark pipelines.

Note

The function does not currently match the JavaScript behavior and will be changed in the near future. In particular, the argument is treated as a JSON-Path instead of a plain property name and it will return false if the property exists, but the value is null. Most expressions should continue to work as expected since they are not qualified paths. If your expression passes a JSON-Path or if the property value is null, use the hasPath method instead.

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'

hasPath

...

Paste code macro
object.hasPath(field)

...

Expression: $.hasPath("Id")

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

isEmpty

...

Returns true if the given object has no properties.

Note
This function is not supported in Spark pipelines.

...

Code Block
object.isEmpty()

...

Expression: {}.isEmpty()

Result: Returns true.

Expression: { foo: 1 }.isEmpty()

Result: Returns false.

filter

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

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"))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

Returns a boolean value to indicate 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 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 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("route") where $ object corresponds to my.custom.route

Result: Returns true.

Expression: $.hasOwnProperty("custom.route") where $ object corresponds to my.custom.route

Result:

Returns false if the value of route is null as custom.route is not a property but a path. (Reason to use hasPath() function instead.)
Returns true if the value of route is not null though custom.route is not a property but a path.

Expression: To create a ternary conditional expression:

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

hasPath

Description

Returns a boolean value to indicate whether the object has the specified property (path) that carries a non-null value. This method is recommended when working with JSONPath, especially when looking for fields nested deep within the object.

Info
Instead of chaining multiple sub-expressions using the hasOwnProperty method to 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(JSONPath.to.property)

Example

Expression: $.hasPath("route") where $ object corresponds to my.custom.route

Result: Returns true.

Expression: $.hasPath("custom.route") where $ object corresponds to my.custom.route

Result:

Returns false if the value of route is null.
Returns true if the value of route is not null.

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 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.

filter

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]

...

Expression: $.mapKeys((value, key) => "new" + key)

Description

Transform the names of properties in an object using a callback.

This is similar to https://lodash.com/docs/4.17.4#mapKeys

Syntax

Code Block
object.mapKeys(callback)

callback - A function that takes three arguments (property-value, property-name, input-object) and returns the new value for the property key.

Example

Expression: $.mapKeys((value, key) => "new" + key)

Input:

Code Block
{ "Field1": "foo", "Field2": "bar" }

Result:

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

...

Description

Transform the values of properties in an object using a callback.

This is similar to https://lodash.com/docs/4.17.4#mapValues

Syntax

Code Block
object.mapValues(callback)

callback - A function that takes three arguments (property-value, property-name, input-object) and returns the new value for the property.

Example

Expression: $.mapValues((value, key) => key == "newField1" ? "foo" : "bar")== "newField1" ? "foo" : "bar")

Input:

Code Block
{ "newField1": "abc", "newField2": "xyz" }

Result:

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

...

let user = { name

[{“user”: {
    “name”: "John",

age

    “age”: 30
    }
}]

Expression: $user.values()
Result: ["John", 30]

Description

Returns an array containing the given object's own enumerable property values. See also entries, keys.

Syntax

Code Block
property.values()

Example

Input:

Code Block

...

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 32

New Version Current

Key

Object Literals

Object Literals

getFirst

hasPath

isEmpty

filter

hasOwnProperty

hasPath

isEmpty

filter

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.

Page Comparison

Versions Compared

Old Version 32

New Version Current

Key

Object Literals

Object Literals

getFirst

hasPath

isEmpty

filter

hasOwnProperty

hasPath

isEmpty

filter

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.