const util = require('util');
// Example values
const values = [
'string',
123,
true,
Symbol('symbol'),
{ key: 'value' },
[1, 2, 3],
null,
undefined,
() => {},
BigInt(123),
new Date(),
/regex/,
Buffer.from('buffer'),
new Error('error')
];
// Check types for each value
values.forEach(value => {
console.log(`Value: ${util.inspect(value)}`);
console.log(`- isArray: ${util.types.isArrayBuffer(value)}`);
console.log(`- isDate: ${util.types.isDate(value)}`);
console.log(`- isRegExp: ${util.types.isRegExp(value)}`);
console.log(`- isNativeError: ${util.types.isNativeError(value)}`);
console.log(`- isPromise: ${util.types.isPromise(value)}`);
console.log(`- isPrimitive: ${util.isPrimitive(value)}`);
console.log(`- isString: ${util.isString(value)}`);
console.log(`- isNumber: ${util.isNumber(value)}`);
console.log(`- isBoolean: ${util.isBoolean(value)}`);
console.log(`- isSymbol: ${typeof value === 'symbol'}`);
console.log(`- isNull: ${value === null}`);
console.log(`- isUndefined: ${value === undefined}`);
console.log(`- isFunction: ${typeof value === 'function'}`);
console.log(`- isBuffer: ${Buffer.isBuffer(value)}`);
console.log('---');
});
Value: 'string'
- isArray: false
- isDate: false
- isRegExp: false
- isNativeError: false
- isPromise: false
- isPrimitive: true
- isString: true
- isNumber: false
- isBoolean: false
- isSymbol: false
- isNull: false
- isUndefined: false
- isFunction: false
- isBuffer: false
---
Value: 123
- isArray: false
- isDate: false
- isRegExp: false
- isNativeError: false
- isPromise: false
- isPrimitive: true
- isString: false
- isNumber: true
- isBoolean: false
- isSymbol: false
- isNull: false
- isUndefined: false
- isFunction: false
- isBuffer: false
---
Value: true
- isArray: false
- isDate: false
- isRegExp: false
- isNativeError: false
- isPromise: false
- isPrimitive: true
- isString: false
- isNumber: false
- isBoolean: true
- isSymbol: false
- isNull: false
- isUndefined: false
- isFunction: false
- isBuffer: false
---
Value: Symbol(symbol)
- isArray: false
- isDate: false
- isRegExp: false
- isNativeError: false
- isPromise: false
- isPrimitive: true
- isString: false
- isNumber: false
- isBoolean: false
- isSymbol: true
- isNull: false
- isUndefined: false
- isFunction: false
- isBuffer: false
---
Value: { key: 'value' }
- isArray: false
- isDate: false
- isRegExp: false
- isNativeError: false
- isPromise: false
- isPrimitive: false
- isString: false
- isNumber: false
- isBoolean: false
- isSymbol: false
- isNull: false
- isUndefined: false
- isFunction: false
- isBuffer: false
---
Value: [ 1, 2, 3 ]
- isArray: true
- isDate: false
- isRegExp: false
- isNativeError: false
- isPromise: false
- isPrimitive: false
- isString: false
- isNumber: false
- isBoolean: false
- isSymbol: false
- isNull: false
- isUndefined: false
- isFunction: false
- isBuffer: false
---
Value: null
- isArray: false
- isDate: false
- isRegExp: false
- isNativeError: false
- isPromise: false
- isPrimitive: true
- isString: false
- isNumber: false
- isBoolean: false
- isSymbol: false
- isNull: true
- isUndefined: false
- isFunction: false
- isBuffer: false
---
Value: undefined
- isArray: false
- isDate: false
- isRegExp: false
- isNativeError: false
- isPromise: false
- isPrimitive: true
- isString: false
- isNumber: false
- isBoolean: false
- isSymbol: false
- isNull: false
- isUndefined: true
- isFunction: false
- isBuffer: false
---
Value: [Function (anonymous)]
- isArray: false
- isDate: false
- isRegExp: false
- isNativeError: false
- isPromise: false
- isPrimitive: false
- isString: false
- isNumber: false
- isBoolean: false
- isSymbol: false
- isNull: false
- isUndefined: false
- isFunction: true
- isBuffer: false
---
Value: 123n
- isArray: false
- isDate: false
- isRegExp: false
- isNativeError: false
- isPromise: false
- isPrimitive: true
- isString: false
- isNumber: false
- isBoolean: false
- isSymbol: false
- isNull: false
- isUndefined: false
- isFunction: false
- isBuffer: false
---
Value: 2025-05-22T06:26:41.138Z
- isArray: false
- isDate: true
- isRegExp: false
- isNativeError: false
- isPromise: false
- isPrimitive: false
- isString: false
- isNumber: false
- isBoolean: false
- isSymbol: false
- isNull: false
- isUndefined: false
- isFunction: false
- isBuffer: false
---
Value: /regex/
- isArray: false
- isDate: false
- isRegExp: true
- isNativeError: false
- isPromise: false
- isPrimitive: false
- isString: false
- isNumber: false
- isBoolean: false
- isSymbol: false
- isNull: false
- isUndefined: false
- isFunction: false
- isBuffer: false
---
Value: <Buffer 62 75 66 66 65 72>
- isArray: false
- isDate: false
- isRegExp: false
- isNativeError: false
- isPromise: false
- isPrimitive: false
- isString: false
- isNumber: false
- isBoolean: false
- isSymbol: false
- isNull: false
- isUndefined: false
- isFunction: false
- isBuffer: true
---
Value: Error: error
at Object.<anonymous> (C:\work\nodejstut\app.js:18:3)
at Module._compile (node:internal/modules/cjs/loader:1730:14)
at Object..js (node:internal/modules/cjs/loader:1895:10)
at Module.load (node:internal/modules/cjs/loader:1465:32)
at Function._load (node:internal/modules/cjs/loader:1282:12)
at TracingChannel.traceSync (node:diagnostics_channel:322:14)
at wrapModuleLoad (node:internal/modules/cjs/loader:235:24)
at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:170:5)
at node:internal/main/run_main_module:36:49
- isArray: false
- isDate: false
- isRegExp: false
- isNativeError: true
- isPromise: false
- isPrimitive: false
- isString: false
- isNumber: false
- isBoolean: false
- isSymbol: false
- isNull: false
- isUndefined: false
- isFunction: false
- isBuffer: false
---