Setting Default Values for Props

• quiz
• easy
• ui
• 7 min
• ui-props
• mark done

In React and Vue, components can declare default values for props so that the parent does not have to pass every prop explicitly. Understanding the exact rules prevents bugs where a parent unintentionally overrides a default.

In React 19, how do you give a function component's `size` prop a default of `"medium"`?

• A function MyComp({ size = "medium" }) { ... }
• B MyComp.defaultProps = { size: "medium" }
• C Both are valid in React 19
• D Only class components can have defaults

In Vue 3, which option correctly sets a default value of `10` for a prop named `max`?

• A props: { max: { default: 10 } }
• B props: { max: { value: 10 } }
• C props: { max: 10 }
• D props: { max: { required: true, default: 10 } }

Which statement about prop default values is true across React and Vue?

• A Default values are only used when the parent passes undefined.
• B Default values are used when the parent passes null.
• C In React, default values are ignored if the prop is an empty string.
• D In Vue, default values must be primitive types.

Related

• Reading: Props · Component
• Agent Skill: ui-props