Display Value

Converts values to a readable display string

displayValue(value, [settings]) ⇒ string

Designed for use in test messages, displayValue takes a javascript value and returns a human readable string representation of that value.

Notes:

• finite numbers are passed through number.toLocaleString()
  • -0 is rendered as -0
  • 1300 is rendered as 1,300 (depending on locale)
• strings are wrapped in double quotes
• Arrays and Objects are passed through a function similar to JSON.stringify, but values are individually run through displayValue
• Array-like values such as arguments are handled like Arrays
• Object-like values such as ClientRect and DOMRect are handled like Objects
• Constructors will return the constructor's name
• Instances of non-native constructors:
  • will return the result of .toString() if other than '[object Object]'
  • otherwise returns '[object Name]' where Name is the constructor's name

Param	Type	Default	Description
value	*
[settings]	Object
[settings.beautify]	Boolean	false	If true and value is an Array or Object then the output is rendered in multiple lines with indentation
[settings.preferJson]	Boolean	true	If true then keys and strings are wrapped in double quotes, similar to JSON.stringify.
[settings.preferSingleQuote]	Boolean	false	If true then strings will be wrapped in single quotes. Only applicable if preferJson is false.

Example

import displayValue from 'display-value';

displayValue(-0); // '-0'
displayValue(1300000); // '1,300,000'
displayValue('foo'); // '"foo"'
displayValue({x: 1}); // '{"x": 1}'

displayValue(() => {}); // '() => {…}'
displayValue(function(param) {}); // 'ƒ (param) {…}'
displayValue(function name() {}); // 'ƒ name() {…}'

displayValue(Symbol()); // 'Symbol()'
displayValue(Symbol('name')); // 'Symbol(name)'

displayValue(new CustomClass()); // '[object CustomClass]'

displayValue([{x: 1}, {x: 2000}], {beautify: true});
// '[
//     {
//         "x": 1
//     }, {
//         "x": 2,000
//     }
// ]'