💾isPrimitive()

check if value is a primitive

JS ⟩ values ⟩ custom functions ⟩ isPrimitive()

replit：isPrimitive()

┌── (primitive ?)
│  typeof       type         expr         value       
---------------------------------------------------------------------
✅ object       Null         null         null
---------------------------------------------------------------------
✅ undefined    Undefined    undefined    undefined
---------------------------------------------------------------------
✅ number       Number       37

replit：isPrimitive()

// ⭐ check if value is object
function isObject(value) {
    return value === Object(value)
}

// ⭐ check if value is primitive
function isPrimitive(value) {
    return !isObject(value)
}

// export
module.exports = { isObject, isPrimitive };

Infinity, NaN are primitives.

The Object constructor's behavior depends on the input's type, if the value is

or ：empty object is returned.
an object already：the value itself is returned.
otherwise：object of a Type that corresponds to the value is returned.

Object(value) is identically to new Object(value)

replit：isPrimitive()
require：test cases from typeName()

// ⭐ import (functions for type name)
const { typeName, baseTypeName } = require('./typeNames.js');
const { testCases } = require('./testCases.js');
const { isPrimitive } = require('./isPrimitive.js');

// table settings
const header = ['typeof', 'type', 'expr', 'value'];
const cols = header.length;
const [width, pad, ext] = [12, 1, 18];
const line = '-'.repeat(width*cols + pad*(cols-1) + ext);

// header
console.log('  ', ...header.map(s => s.padEnd(width, ' ')));
console.log(line);

// rows
for (const testCase of testCases) {

    // separator
    if (testCase === '---') {
        console.log(line); 
        continue; 
    }
    
    // test cases
    const value = testCase[0];
    const expr = testCase[1] || String(testCase[0]);

    const types = [typeof value, typeName(value)];
    const numberOfDifferentTypes = new Set(types.map(s => s.toLowerCase())).size;

    console.log(
         isPrimitive(value) ? '✅' : '❌',
        ...[...types, expr].map(s => s.padEnd(width, ' ')),
        value,
    )
}

console.log(line);

// legend
console.log(`• ⭐️ types not all the same        • ❗ base !== type`);

PreviousisObject()NextisFunction()

Last updated 2 years ago

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┌── (primitive ?) │ typeof type expr value --------------------------------------------------------------------- ✅ object Null null null --------------------------------------------------------------------- ✅ undefined Undefined undefined undefined --------------------------------------------------------------------- ✅ number Number 37

// ⭐ check if value is object function isObject(value) { return value === Object(value) } // ⭐ check if value is primitive function isPrimitive(value) { return !isObject(value) } // export module.exports = { isObject, isPrimitive };

// ⭐ import (functions for type name) const { typeName, baseTypeName } = require('./typeNames.js'); const { testCases } = require('./testCases.js'); const { isPrimitive } = require('./isPrimitive.js'); // table settings const header = ['typeof', 'type', 'expr', 'value']; const cols = header.length; const [width, pad, ext] = [12, 1, 18]; const line = '-'.repeat(width*cols + pad*(cols-1) + ext); // header console.log(' ', ...header.map(s => s.padEnd(width, ' '))); console.log(line); // rows for (const testCase of testCases) { // separator if (testCase === '---') { console.log(line); continue; } // test cases const value = testCase[0]; const expr = testCase[1] || String(testCase[0]); const types = [typeof value, typeName(value)]; const numberOfDifferentTypes = new Set(types.map(s => s.toLowerCase())).size; console.log( isPrimitive(value) ? '✅' : '❌', ...[...types, expr].map(s => s.padEnd(width, ' ')), value, ) } console.log(line); // legend console.log(`• ⭐️ types not all the same • ❗ base !== type`);