TL;DR

Vue 2.7 has received its final release, addressing a critical bug that could cause memory leaks in long-lived components due to improperly disconnected effect scopes.

Breaking

• None

New

None

Fixes Worth Knowing

• Corrected a memory leak (unintentional memory usage) in components that remain active for extended periods.

Before You Upgrade

No action needed – this is a recommended update for all Vue 2.7 users.

TL;DR

Vue 2.7 receives significant improvements to TypeScript definitions, enhancing developer experience and enabling better type checking for components and built-in features.

Breaking

• Typescript: More types are now exported for alignment with Vue 3, potentially requiring adjustments to existing type declarations (JSX, component options).

New

• Typescript: Improved type definitions for built-in components.
• Typescript: Enhanced type augmentation and support for bundler module resolution.

Fixes Worth Knowing

• Keep-alive: Resolved memory leaks in the <keep-alive> component, improving application stability.
• Templates: Correctly handles nested render calls and stringifies reactive values, preventing unexpected behavior.
• Watchers: Deep watchers now correctly trigger on new property additions.

Before You Upgrade

Review your custom TypeScript definitions, especially if you are using JSX or custom component options, to ensure compatibility with the updated type exports.

TL;DR

Vue.js is more stable with fixes addressing regressions introduced in recent releases, particularly around component updates and prop handling.

Breaking

• v-if with v-ref (component references) no longer throws errors.
• nextTick behavior is reverted to microtask semantics, resolving issues on older iOS versions.

Fixes Worth Knowing

• $refs now updates correctly within v-if blocks.
• Checkbox v-model updates now correctly replace values in bound arrays.
• Prop validation now works correctly when using propsData (component properties passed directly).
• Filters with spaces in arguments are now parsed correctly.

Before You Upgrade

No specific action is needed, this release focuses on stability improvements.

TL;DR

Vue now supports more flexible v-for loops and simplified event handling with modifiers, improving component development and reducing boilerplate.

Breaking

• Custom directives: The undocumented this.param() method is removed; use the new params array instead. (Directive attributes)

New

• v-for loops can now access keys and indexes directly: v-for="(key, val) in obj" or v-for="(index, val) in arr".
• Event listeners with modifiers are simplified: @submit.prevent now calls preventDefault() directly.

Fixes Worth Knowing

• Corrected issues with prop merging, component detachment in v-for loops, directive scope, and dynamic class updates.

Before You Upgrade

Update any custom directives using this.param() to utilize the new params array API.

TL;DR

Vue.js now allows filters within $watch expressions and significantly improves performance when filtering large arrays (over 5000 items).

Breaking

None.

New

• $watch expressions now support Vue filters (text transformations).
• Vue.mixin() allows plugins to inject custom behavior (advanced usage).

Fixes Worth Knowing

• Corrected issues with <select v-model> when using number arrays.
• Fixed transitions getting stuck when elements are hidden with CSS.
• Resolved unnecessary updates with v-model in lazy mode.

Before You Upgrade

No action needed.

TL;DR

Vue underwent a major overhaul, introducing asynchronous components (components that load on demand) and a revamped transition system allowing CSS transitions and JavaScript hooks to work together.

Breaking

• paramAttributes is now props.
• v-with and v-component are removed; use props and the <component is="..."> syntax respectively.
• v-partial and {{> partial}} are removed.
• Filter arguments now treat non-quoted values as dynamic paths.

New

• Async Components: Load component definitions on demand for improved performance.
• Element Directives: Treat custom elements as directives for greater control.

Fixes Worth Knowing

• v-repeat now handles object iteration and array updates more reliably.
• Props are now correctly persisted when $data is replaced.

Before You Upgrade

• Update all instances of paramAttributes to props.
• Replace v-with with props and v-component with <component is="...">.
• Review and update any code using v-partial or {{> partial}}.