ktlint-format-example

Sample application that calls the ktlint formatter from the Kotlin source code

fun main() {
    val code = """
        class Foo(
        val id : String, val age : Int,
        val name:String )
        {
            fun foo() : Boolean { return name.isEmpty()
        }
        }
    """.trimIndent()

    val ruleSets = setOf(
        StandardRuleSetProvider().get()
    )
    val formatted = KtLint.format(
        KtLint.Params(
            fileName = null,
            text = code,
            ruleSets = ruleSets,
            userData = emptyMap(),
            cb = { _, _ -> run {} },
            script = false,
            editorConfigPath = null,
            debug = false
        )
    )

    println(formatted)
}

// Output:
//
// class Foo(
//     val id: String,
//     val age: Int,
//     val name: String
// ) {
//     fun foo(): Boolean {
//         return name.isEmpty()
//     }
// }

Standard rules

Rule	Format	Test
Indentation formatting	o
No semicolons	o
No unused imports	o
No consecutive blank lines	o
No blank lines before }	o
No trailing whitespaces	o
No Unit returns	o
No empty ({}) class bodies	o
No wildcard imports	x
When wrapping chained calls ., ?. and ?: should be placed on the next line	o
When a line is broken at an assignment (=) operator the break comes after the symbol	o
When class/function signature doesn't fit on a single line, each parameter must be on a separate line	o
Consistent string templates	o
Consistent order of modifiers	o
Consistent spacing after keywords, commas; around colons, curly braces, parens, infix operators, comments, range operators, etc	o
Newline at the end of each file	o
Imports ordered consistently	o

Experimental rules

Rule	Format	Test
Annotation formatting	o
Annotations should be separated by the annotated declaration by a single line break	o
Argument list wrapping	o
Enum entry names should be uppercase underscore-separated names	o
Braces required for multiline if/else statements	o
No leading empty lines in method blocks	o
No underscores in package names	x
No spaces around angle brackets	o
No spaces around ::	o
No spaces around unary operators	o
Declarations with annotations should be separated by a blank line	o
Declarations with comments should be separated by a blank line	o