Programming languages all have built-in data structures, but these often differ from one language to another. This article attempts to list the built-in data structures available in JavaScript and what properties they have. These can be used to build other data structures. Wherever possible, comparisons with other languages are drawn.
Dynamic typing
JavaScript is a loosely typed and dynamic language. Variables in JavaScript are not directly associated with any particular value type, and any variable can be assigned (and re-assigned) values of all types:
let foo = 42; // foo is now a number
foo = ‘bar’; // foo is now a string
foo = true; // foo is now a boolean
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Aenean feugiat eros vel imperdiet placerat. Suspendisse auctor nec ipsum eget tempus. Aliquam erat volutpat. Nulla mattis dui dolor, ut auctor nisi aliquam sed. Sed lorem augue, condimentum porta massa id, sollicitudin gravida eros. Aenean non libero erat. Aliquam erat volutpat. Aliquam erat volutpat. Quisque porttitor dignissim felis, id aliquet felis viverra a. Aliquam congue faucibus urna.
Maecenas sodales, sem quis vestibulum pellentesque, orci risus iaculis purus, a finibus mi erat ut lectus. Nunc consequat enim eu mauris molestie rhoncus. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Sed sapien odio, malesuada ac sem varius, lacinia sollicitudin risus. In auctor, purus rhoncus fermentum ultrices, dolor risus scelerisque ligula, sed ornare neque diam id lectus. Nam sagittis pulvinar posuere. Sed ligula est, consectetur in diam nec, fermentum gravida est. Aenean vitae ultrices justo. Mauris ultricies turpis egestas turpis pharetra, in commodo lacus ultricies.
Programming languages all have built-in data structures, but these often differ from one language to another. This article attempts to list the built-in data structures available in JavaScript and what properties they have. These can be used to build other data structures. Wherever possible, comparisons with other languages are drawn.
Dynamic typing
JavaScript is a loosely typed and dynamic language. Variables in JavaScript are not directly associated with any particular value type, and any variable can be assigned (and re-assigned) values of all types:
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Aenean feugiat eros vel imperdiet placerat. Suspendisse auctor nec ipsum eget tempus. Aliquam erat volutpat. Nulla mattis dui dolor, ut auctor nisi aliquam sed. Sed lorem augue, condimentum porta massa id, sollicitudin gravida eros. Aenean non libero erat. Aliquam erat volutpat. Aliquam erat volutpat. Quisque porttitor dignissim felis, id aliquet felis viverra a. Aliquam congue faucibus urna.
Maecenas sodales, sem quis vestibulum pellentesque, orci risus iaculis purus, a finibus mi erat ut lectus. Nunc consequat enim eu mauris molestie rhoncus. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Sed sapien odio, malesuada ac sem varius, lacinia sollicitudin risus. In auctor, purus rhoncus fermentum ultrices, dolor risus scelerisque ligula, sed ornare neque diam id lectus. Nam sagittis pulvinar posuere. Sed ligula est, consectetur in diam nec, fermentum gravida est. Aenean vitae ultrices justo. Mauris ultricies turpis egestas turpis pharetra, in commodo lacus ultricies.