es6format.js

String formatting that replicates the ES6 template operator but executes at runtime.

INSTALLATION

1	npm install es6format

USAGE

1	const format = require( "es6format" );
2	console.log(
3		format( "Hello, ${0}!", "World" )
4	);
5	// output: Hello, World!
6
7	format.bindTo( String, 'using' );
8	console.log(
9		"Hello, ${0}!".using( "World" )
10	);
11	// output: Hello, World!

DOCUMENTATION

Usage is straightforward:

1	format( <template-string>, ...args )	

Arguments passed to the function are made available to the template via the following ways:

index ${0}

to reference arugments by order

1          format( "Hello, ${0}!", "World" );

strings ${name}

to reference any fields of arguments

1          format( "Call me ${name}.", { name : "Ishmael" });

NOTE: in cases where multiple arguments include the same field, the last argument takes precidence. Use fully defined object references to get access to the others. See below

1          format(
2            "Don't call me ${name}.",
3            { name : "Ishmael" },
4            { name : "Bob"}
5          );

'arg'+index ${arg1}

to use arguments within expressions or to access argument fields. Particularly handy to disambiguate fields when multiple arguments have them (e.g. ${arg2.name})

1          format(
2            "Using ${name} gives you ${arg1.name} not ${arg0.name}",
3            { name : "Ishmael" },
4            { name : "Bob"}
5          );

to use the argument in a function

1          format( "B is letter ${arg0.indexOf('B')} letter", "ABC" );

expressions ${a + b}

1          format( "the sum of ${a} and ${b} is ${a + b}", {a: 2, b: 5} );

methods ${arg3.method()}

1          format( "Please don't ${arg0.toLowerCase()}", "YELL" );

args[index] ${args[3]}

to reference arugments programatically (e.g. ${args[arg0]})

1          format( "I am ${args[arg0]}", 1, "right", "wrong" )

${x=3}

to set values for use later in the format string (e.g. ${x=a+3})

1          format(
2            "${arg0}^2 is ${x=arg0*arg0}, and squared again is ${x*x}",
3            3
4          )

Arbitrary code ${ ...some computation } or ${ ...some computation, 'output' }

1          format(
2            "my favorite mice are ${ args.join(' mouse, ') }",
3            "Mickey", "Minie", "Mighty"
4          )

and

1         format(
2            "the password is a ${ arg0.substring( arg0.indexOf( '{' ) + 1, arg0.indexOf( '}' ))}",
3            "hidden{secret}within"
4          )

and

1         format(
2            "x.a is ${ x = { a : arg0 + arg1 }, 'set' } to ${x.a}",
3            2, 3
4          )

and even,

1         format(
2          	"${args.reduce((o,i)=>{if (o<3) return o+i; return i})}",
3          	1,2,3,4,5,6,7
4         )

WARNING

es6format makes use of Function(), so it should never be called on format strings that are not known to be safe.