Printing valid JSON with a Swift script

I am attempting to print out in the command line the contents of a variable that holds a JSON object, like in the code:

#! /usr/bin/swift
import Glibc
import Foundation

let albert_op = ProcessInfo.processInfo.environment["ALBERT_OP"]!


if albert_op == "METADATA" {
    let metadata = [
        ["iid": "org.albert.extension.external/v2.0",
        "name": "Tomboy",
        "version": "0.1",
        "author": "Will Timpson",
        "dependencies": ["tomboy", "python-pydbus"],
        "trigger": "tb "]
    ]
    print(metadata))
}


exit(0)

However, that prints out:

[["trigger": "tb ", "name": "Tomboy", "iid": "org.albert.extension.external/v2.0", "dependencies": ["tomboy", "python-pydbus"], "version": "0.1", "author": "Will Timpson"]]

Which is not valid, I was expecting something like:

{"version": "0.1", "author": "Will Timpson", "iid": "org.albert.extension.external/v2.0", "trigger": "tb ", "dependencies": ["tomboy", "python-pydbus"], "name": "Tomboy"}

• How to achieve the proper result?

Two issues:

1. You don't have the structure you ultimately want. You have an array with one item in it, and that item is a dictionary. Based on your expected output, you seem to just want a dictionary. You can fix this by dropping the extra square brackets.
2. JSON is a serialization format. You don't have "a JSON object." You have data that you would like to serialize as JSON. You can do that with JSONSerialization.

Here's working code that produces the expected output:

#! /usr/bin/swift

import Foundation

// Drop the extra brackets, and use a type annotation
let metadata: [String: Any] = [
    "iid": "org.albert.extension.external/v2.0",
    "name": "Tomboy",
    "version": "0.1",
    "author": "Will Timpson",
    "dependencies": ["tomboy", "python-pydbus"],
    "trigger": "tb"
]

// Serialize to JSON
let jsonData = try JSONSerialization.data(withJSONObject: metadata)

// Convert to a string and print
if let JSONString = String(data: jsonData, encoding: String.Encoding.utf8) {
   print(JSONString)
}

// Output:
// {"iid":"org.albert.extension.external\/v2.0","name":"Tomboy","version":"0.1","dependencies":["tomboy","python-pydbus"],"author":"Will Timpson","trigger":"tb"}