FormatString

formatString

string

A string with placeholders.

…args [ Rest Parameter ]

any[]

Any value used in a placeholder.

string | null

String in which the placeholders are replaced by values of the symbols or null if anything other than string is passed as formatString.

{

Placeholder is initiated.

0

Index of the parameter (optional: without an index iteration takes place in sequence).

|

Separator.

+

If a + is specified here, the string is always assigned a sign. For example "+42" for the positive number 42. Negative numbers of course always get a sign.

.X

Number of digits.

f

Type description.

}

End of the placeholder.

d

Signed decimal integer

i

Signed decimal integer

u

Unsigned decimal integer

o

Unsigned octal

x

Unsigned hexadecimal integer

X

Unsigned hexadecimal integer (upper case)

f

Decimal floating point

e

Scientific notation (mantissa/exponent), lower case

g

Use the shortest representation: e or f

s

String of characters

b

Binary number

t

true or false

T

Type of the argument ('number', 'string', 'null' …)

v

Primitive value of the specified argument

j

JavaScript object or array as a JSON encoded string