The most advanced function here is util.format()
Methods
format(f) → string
static
Returns a formatted string using the first argument as a printf-like format.
The first argument is a string that contains zero or more placeholders. Each placeholder is replaced with the converted value from its corresponding argument. Supported placeholders are:
- %s - String.
- %d - Number (both integer and float).
- %j - JSON.
- % - single percent sign ('%'). This does not consume an argument.
If the placeholder does not have a corresponding argument, the placeholder is not replaced:
util.format('%s:%s', 'foo'); // 'foo:%s'
If there are more arguments than placeholders, the extra arguments are converted to strings with util.inspect() and these strings are concatenated, delimited by a space:
util.format('%s:%s', 'foo', 'bar', 'baz'); // 'foo:bar baz'
If the first argument is not a format string then util.format() returns a string that is the concatenation of all its arguments separated by spaces. Each argument is converted to a string with util.inspect():
util.format(1, 2, 3); // '1 2 3'
Arguments:
-
f
print(…arguments)
inner
A synchronous output function. Will block the process, cast each argument to a string then output to stdout. Does not place newlines after each argument:
util.print('one', 'two', 3); // onetwo3
Arguments:
-
...arguments (*)
puts(…arguments)
inner
A synchronous output function. Will block the process and output all arguments to stdout with newlines after each argument.
util.puts('one', 'two', 3); // one
// two
// 3
Arguments:
-
...arguments (*)
debug(msg)
inner
Will block the process and output string immediately to stderr:
require('util').debug('message on stderr');
Arguments:
-
msg (*)
error(…arguments)
inner
Same as util#debug except this will output all arguments immediately to stderr.
Arguments:
-
...arguments (*)
inspect(obj, opts)
inner
Echos the value of a value. Trys to print the value out
in the best way possible given the different types.
Arguments:
isArray(ar) → boolean
inner
Arguments:
-
ar
isRegExp(re) → boolean
inner
Arguments:
-
re
isDate(d) → boolean
inner
Arguments:
-
d
isError(e) → boolean
inner
Arguments:
-
e
log(msg)
static
Output with timestamp on stdout.
Arguments:
-
msg (String)
inherits(ctor, superCtor)
inner
Inherit the prototype methods from one constructor into another.
The Function.prototype.inherits from lang.js rewritten as a standalone
function (not on Function.prototype). NOTE: If this file is to be loaded
during bootstrapping this function needs to be rewritten using some native
functions as prototype setup using normal JavaScript does not work as
expected during bootstrapping (see mirror.js in r114903).
Arguments:
-
ctor (function) Constructor function which needs to inherit the
prototype.
-
superCtor (function) Constructor function to inherit prototype from.
Returns a formatted string using the first argument as a printf-like format.
The first argument is a string that contains zero or more placeholders. Each placeholder is replaced with the converted value from its corresponding argument. Supported placeholders are:
- %s - String.
- %d - Number (both integer and float).
- %j - JSON.
- % - single percent sign ('%'). This does not consume an argument.
If the placeholder does not have a corresponding argument, the placeholder is not replaced:
util.format('%s:%s', 'foo'); // 'foo:%s'If there are more arguments than placeholders, the extra arguments are converted to strings with util.inspect() and these strings are concatenated, delimited by a space:
util.format('%s:%s', 'foo', 'bar', 'baz'); // 'foo:bar baz'If the first argument is not a format string then util.format() returns a string that is the concatenation of all its arguments separated by spaces. Each argument is converted to a string with util.inspect():
util.format(1, 2, 3); // '1 2 3'f
A synchronous output function. Will block the process, cast each argument to a string then output to stdout. Does not place newlines after each argument:
util.print('one', 'two', 3); // onetwo3...arguments (*)
A synchronous output function. Will block the process and output all arguments to stdout with newlines after each argument.
util.puts('one', 'two', 3); // one
// two
// 3...arguments (*)
Will block the process and output string immediately to stderr:
require('util').debug('message on stderr');msg (*)
util#debug except this will output all arguments immediately to stderr.
...arguments (*)
ar
re
d
e
msg (String)
The Function.prototype.inherits from lang.js rewritten as a standalone function (not on Function.prototype). NOTE: If this file is to be loaded during bootstrapping this function needs to be rewritten using some native functions as prototype setup using normal JavaScript does not work as expected during bootstrapping (see mirror.js in r114903).
ctor (function) Constructor function which needs to inherit the
prototype.
superCtor (function) Constructor function to inherit prototype from.