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Access

Joelang supports several ways to get data out of arrays, objects, strings, and tuples.

Suppose we have these variables

const arr: string[] = ['A', 'B', 'C', 'D', 'E', 'F', 'G'];

const obj = {
	name: 'Joe',
	hobby: 'Coding',
	friends: ['Moe', 'Larry', 'Curly'],
};

const str = 'ABCDEFG';

const tpl = <1, 'abc', true, 3.14, {name: 'Joe'}>;

Get a single item/property/char

ts
// by numerical index

arr[0] // 'A'

const index = 3;
arr[index] // 'D'
ts
// by property name

// dot notation
obj.name // 'Joe'
obj.friends // ['Moe', 'Larry', 'Curly']

// bracket notation
obj['name'] // 'Joe'

// using a variable
const prop = 'name';
obj[prop] // 'Joe'
ts
// by numerical index

str[0] // 'A'

const index = 3;
str[index] // 'D'
ts
// by numerical index

tpl[0] // 1  ✅

// Please note using a variable to access a Tuple item DOES NOT work
const index = 3;
tpl[index]  ❌

Get multiple items/properties/chars by key

ts
arr[0, 2, 4] // ['A', 'C', 'E']

const keys = [0, 2, 4];
arr[...keys] // ['A', 'C', 'E']
ts
obj['name', 'hobby'] // {name: 'Joe', hobby: 'Coding'}

const properties = ['name', 'friends'];
obj[...properties] // {name: 'Joe', friends: ['Moe', 'Larry', 'Curly']}
ts
str[0, 2, 4] // 'ACE'

const keys = [0, 2, 4];
str[...keys] // 'ACE'
ts
tpl[0, 2, 4] // <1, true, {name: 'Joe'}>

const keys = [0, 2, 4];
tpl[...keys] // <1, true, {name: 'Joe'}>

Get multiple items/properties/chars by Range

DANGER

Ranges are not supported on Objects since they are not numerically indexed

ts
// valid way to access range from an array
arr[1 .. 3]; // ['B', 'C', 'D']  ✅

// using variables for range bounds
const lower = 1;
const upper = 3;
arr[lower .. upper] // ['B', 'C', 'D']  ✅

// invalid since the range is a variable
const myRange = 1 .. 3;
arr[myRange];  ❌
arr[myRange.lower .. myRange.upper]  ✅
ts
// valid way to access range from a string
str[1 .. 3]; // 'BCD'  ✅

// using variables for range bounds
const lower = 1;
const upper = 3;
str[lower .. upper] // 'BCD'  ✅

// invalid since the range is a variable
const myRange = 1 .. 3;
str[myRange];  ❌
str[myRange.lower .. myRange.upper]  ✅
ts
// valid way to access range from a tuple
tpl[1 .. 3] // <'abc', true, 3.14>

// using variables for range bounds
const lower = 1;
const upper = 3;
tpl[lower .. upper] // <'abc', true, 3.14>  ✅

// invalid since the range is a variable
const myRange = 1 .. 3;
tpl[myRange];  ❌
tpl[myRange.lower .. myRange.upper]  ✅

WARNING

Range variables are not supported due to limitations of the parser. Instead of passing the range variable directly, pass the lower and upper bounds individually.

TIP

Use variables for range bounds instead.