How can I get the full object in Node.js's console.log(), rather than '[Object]'?

Question

When debugging using console.log(), how can I get the full object?

const myObject = {
   \"a\":\"a\",
   \"b\":{
      \"c\":\"c\",
      \"d\":         


        

Answer 1

^{A compilation of the many useful answers from (at least) Node.js v0.10.33 (stable) / v0.11.14 (unstable) presumably through (at least) v7.7.4 (the version current as of the latest update to this answer). Tip of the hat to Rory O'Kane for his help.}

tl;dr

To get the desired output for the example in the question, use console.dir():

console.dir(myObject, { depth: null }); // `depth: null` ensures unlimited recursion

Why not util.inspect()? Because it’s already at the heart of diagnostic output: console.log() and console.dir() as well as the Node.js REPL use util.inspect() implicitly. It’s generally not necessary to require('util') and call util.inspect() directly.

Details below.

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• console.log() (and its alias, console.info()):

  • If the 1st argument is NOT a format string: util.inspect() is automatically applied to every argument:
    • o = { one: 1, two: 'deux', foo: function(){} }; console.log(o, [1,2,3]) // -> '{ one: 1, two: 'deux', foo: [Function] } [ 1, 2, 3 ]'
    • Note that you cannot pass options through util.inspect() in this case, which implies 2 notable limitations:
      • Structural depth of the output is limited to 2 levels (the default).
        • Since you cannot change this with console.log(), you must instead use console.dir(): console.dir(myObject, { depth: null } prints with unlimited depth; see below.
      • You can’t turn syntax coloring on.
  • If the 1st argument IS a format string (see below): uses util.format() to print the remaining arguments based on the format string (see below); e.g.:
    • o = { one: 1, two: 'deux', foo: function(){} }; console.log('o as JSON: %j', o) // -> 'o as JSON: {"one":1,"two":"deux"}'
    • Note:
      • There is NO placeholder for representing objects util.inspect()-style.
      • JSON generated with %j is NOT pretty-printed.

• console.dir():

  • Accepts only 1 argument to inspect, and always applies util.inspect() – essentially, a wrapper for util.inspect() without options by default; e.g.:
    • o = { one: 1, two: 'deux', foo: function(){} }; console.dir(o); // Effectively the same as console.log(o) in this case.
  • Node.js v0.11.14+: The optional 2nd argument specifies options for util.inspect() – see below; e.g.:
    • console.dir({ one: 1, two: 'deux'}, { colors: true }); // Node 0.11+: Prints object representation with syntax coloring.

• The REPL: implicitly prints any expression's return value with util.inspect() with syntax coloring;
  i.e., just typing a variable's name and hitting Enter will print an inspected version of its value; e.g.:
  • o = { one: 1, two: 'deux', foo: function(){} } // The REPL echoes the object definition with syntax coloring.

util.inspect() automatically pretty-prints object and array representations, but produces multiline output only when needed.

• The pretty-printing behavior can be controlled by the compact property in the optional options argument; false uses multi-line output unconditionally, whereas true disables pretty-printing altogether; it can also be set to a number (the default is 3) to control the conditional multi-line behavior – see the docs.

• By default, output is wrapped at around 60 characters ^{thanks, Shrey} , regardless of whether the output is sent to a file or a terminal. In practice, since line breaks only happen at property boundaries, you will often end up with shorter lines, but they can also be longer (e.g., with long property values).

• In v6.3.0+ you can use the breakLength option to override the 60-character limit; if you set it to Infinity, everything is output on a single line.

If you want more control over pretty-printing, consider using JSON.stringify() with a 3rd argument, but note the following:

• Fails with objects that have circular references, such as module in the global context.
• Methods (functions) will by design NOT be included.
• You can't opt into showing hidden (non-enumerable) properties.
• Example call:
  • JSON.stringify({ one: 1, two: 'deux', three: true}, undefined, 2); // creates a pretty-printed multiline JSON representation indented with 2 spaces

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util.inspect() options object (2nd argument):

An optional options object may be passed that alters certain aspects of the formatted string; some of the properties supported are:

^{See the latest Node.js docs for the current, full list.}

• showHidden

  • if true, then the object's non-enumerable properties [those designated not to show up when you use for keys in obj or Object.keys(obj)] will be shown too. Defaults to false.

• depth

  • tells inspect how many times to recurse while formatting the object. This is useful for inspecting large complicated objects. Defaults to 2. To make it recurse indefinitely, pass null.

• colors

  • if true, then the output will be styled with ANSI color codes. Defaults to false. Colors are customizable [… – see link].

• customInspect

  • if false, then custom inspect() functions defined on the objects being inspected won't be called. Defaults to true.

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util.format() format-string placeholders (1st argument)

Some of the supported placeholders are:

^{See the latest Node.js docs for the current, full list.}

• %s – String.
• %d – Number (both integer and float).
• %j – JSON.
• %% – single percent sign (‘%’). This does not consume an argument.