Summary:
This article will delve into the diff algorithm in the front-end framework, focusing on the diff algorithm of Vue and React, and introduce the optimization techniques in some other front-end frameworks, including Svelte, Incremental DOM, Mithril, Snabbdom, morphdom and Preact. By comparing their principles and differences, readers can understand the optimization methods of different frameworks, so as to improve the performance and user experience of front-end applications.
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Vue's diff algorithm (Virtual DOM Diffing Algorithm): Vue uses Virtual DOM for rendering optimization. Every time the data is updated, Vue will first generate a new virtual DOM tree, and then compare this new virtual DOM tree with the previous old virtual DOM tree to find the difference. This difference includes adding nodes, deleting nodes, modifying attributes, etc., and finally applying these differences to the actual DOM tree. Such a comparison process avoids frequent operations directly on the actual DOM and improves rendering performance.
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React's diff algorithm (Reconciliation Algorithm): React's diff algorithm is based on two main principles: Nodes with the same element type, React will keep their state and will not re-render; for different types of element nodes, React will destroy the old node and create new nodes. React will recursively compare the two virtual DOM trees before and after, find out the difference, and then use the smallest operation to update the actual DOM.
Before React 16, React used the classic diff algorithm, which is an algorithm with O(n^3) complexity. However, since React 16, React adopts the Fiber architecture and introduces the concepts of incremental rendering and priority scheduling, so that the diff process can be interrupted and resumed, improving rendering performance and user response speed.
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Svelte 's optimization technology: Svelte is a compiled framework that compiles components into efficient JavaScript code during the construction phase without using virtual DOM. In this way, there is no need to compare the diff algorithm at runtime, but to directly generate the code for manipulating the DOM, which reduces the runtime overhead.
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Incremental DOM : Incremental DOM is a technique for diff calculation at runtime, similar to React's incremental rendering. It does not build a complete virtual DOM tree, but directly generates and applies incremental updates, reducing memory overhead and the complexity of the diff algorithm.
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Mithril 's diff algorithm (Redrawing Minimization Algorithm): Mithril uses a binary tree-based diff algorithm, which traverses the two virtual DOM trees in order, compares the nodes, and minimizes the number of DOM updates to improve rendering performance.
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Snabbdom : Snabbdom is a virtual DOM library with a diff algorithm inspired by React. Snabbdom's design goals are to keep it simple and efficient, and to avoid unnecessary DOM updates as much as possible.
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morphdom : morphdom is another virtual DOM library, focusing on finding the minimum difference between the two DOM trees before and after, and updating the DOM. Its focus is on handling large DOM structures quickly.
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Preact 's diff algorithm: Preact is a replacement for React, and its diff algorithm is similar to React, but more streamlined. The goal of Preact is to provide a smaller, faster version of React.
Summary: The diff algorithm of each front-end framework has its unique advantages and design principles. Both Vue and React's diff algorithms use virtual DOM to minimize DOM operations, thereby improving rendering performance. Svelte avoids the overhead of the diff algorithm at runtime through optimization in the compilation phase, while other technologies such as Incremental DOM, Mithril, Snabbdom, morphdom, and Preact have their own characteristics and are suitable for different application scenarios. Choosing the right framework and optimization techniques can be decided based on the needs and performance requirements of the project.