shallow.md

Shallow Rendering API

Shallow rendering is useful to constrain yourself to testing a component as a unit, and to ensure that your tests aren't indirectly asserting on behavior of child components.

As of Enzyme v3, the shallow API does call React lifecycle methods such as componentDidMount and componentDidUpdate. You can read more about this in the version 3 migration guide.

import { shallow } from 'enzyme';
import sinon from 'sinon';
import Foo from './Foo';

describe('<MyComponent />', () => {
  it('renders three <Foo /> components', () => {
    const wrapper = shallow(<MyComponent />);
    expect(wrapper.find(Foo)).to.have.lengthOf(3);
  });

  it('renders an `.icon-star`', () => {
    const wrapper = shallow(<MyComponent />);
    expect(wrapper.find('.icon-star')).to.have.lengthOf(1);
  });

  it('renders children when passed in', () => {
    const wrapper = shallow((
      <MyComponent>
        <div className="unique" />
      </MyComponent>
    ));
    expect(wrapper.contains(<div className="unique" />)).to.equal(true);
  });

  it('simulates click events', () => {
    const onButtonClick = sinon.spy();
    const wrapper = shallow(<Foo onButtonClick={onButtonClick} />);
    wrapper.find('button').simulate('click');
    expect(onButtonClick).to.have.property('callCount', 1);
  });
});

shallow(node[, options]) => ShallowWrapper

Arguments

1. node (ReactElement): The node to render
2. options (Object [optional]):

• options.context: (Object [optional]): Context to be passed into the component
• options.disableLifecycleMethods: (Boolean [optional]): If set to true, componentDidMount is not called on the component, and componentDidUpdate is not called after setProps and setContext. Default to false.
• options.wrappingComponent: (ComponentType [optional]): A component that will render as a parent of the node. It can be used to provide context to the node, among other things. See the getWrappingComponent() docs for an example. Note: wrappingComponent must render its children.
• options.wrappingComponentProps: (Object [optional]): Initial props to pass to the wrappingComponent if it is specified.
• options.suspenseFallback: (Boolean [optional]): If set to true, when rendering Suspense enzyme will replace all the lazy components in children with fallback element prop. Otherwise it won't handle fallback of lazy component. Default to true. Note: not supported in React < 16.6.

Returns

ShallowWrapper: The wrapper instance around the rendered output.

ShallowWrapper API

.find(selector) => ShallowWrapper

Find every node in the render tree that matches the provided selector.

.findWhere(predicate) => ShallowWrapper

Find every node in the render tree that returns true for the provided predicate function.

.filter(selector) => ShallowWrapper

Remove nodes in the current wrapper that do not match the provided selector.

.filterWhere(predicate) => ShallowWrapper

Remove nodes in the current wrapper that do not return true for the provided predicate function.

.hostNodes() => ShallowWrapper

Removes nodes that are not host nodes; e.g., this will only return HTML nodes.

.contains(nodeOrNodes) => Boolean

Returns whether or not a given node or array of nodes is somewhere in the render tree.

.containsMatchingElement(node) => Boolean

Returns whether or not a given react element exists in the shallow render tree.

.containsAllMatchingElements(nodes) => Boolean

Returns whether or not all the given react elements exist in the shallow render tree.

.containsAnyMatchingElements(nodes) => Boolean

Returns whether or not one of the given react elements exists in the shallow render tree.

.equals(node) => Boolean

Returns whether or not the current render tree is equal to the given node, based on the expected value.

.matchesElement(node) => Boolean

Returns whether or not a given react element matches the shallow render tree.

.hasClass(className) => Boolean

Returns whether or not the current node has the given class name or not.

.is(selector) => Boolean

Returns whether or not the current node matches a provided selector.

.exists([selector]) => Boolean

Returns whether or not the current node exists, or, if given a selector, whether that selector has any matching results.

.isEmpty() => Boolean

Deprecated: Use .exists() instead.

.isEmptyRender() => Boolean

Returns whether or not the current component returns a falsy value.

.not(selector) => ShallowWrapper

Remove nodes in the current wrapper that match the provided selector. (inverse of .filter())

.children([selector]) => ShallowWrapper

Get a wrapper with all of the children nodes of the current wrapper.

.childAt(index) => ShallowWrapper

Returns a new wrapper with child at the specified index.

.parents([selector]) => ShallowWrapper

Get a wrapper with all of the parents (ancestors) of the current node.

.parent() => ShallowWrapper

Get a wrapper with the direct parent of the current node.

.closest(selector) => ShallowWrapper

Get a wrapper with the first ancestor of the current node to match the provided selector.

.shallow([options]) => ShallowWrapper

Shallow renders the current node and returns a shallow wrapper around it.

.render() => CheerioWrapper

Returns a CheerioWrapper of the current node's subtree.

.renderProp(key)() => ShallowWrapper

Returns a wrapper of the node rendered by the provided render prop.

.unmount() => ShallowWrapper

A method that un-mounts the component.

.text() => String

Returns a string representation of the text nodes in the current render tree.

.html() => String

Returns a static HTML rendering of the current node.

.get(index) => ReactElement

Returns the node at the provided index of the current wrapper.

.getElement() => ReactElement

Returns the wrapped ReactElement.

.getElements() => Array<ReactElement>

Returns the wrapped ReactElements.

.at(index) => ShallowWrapper

Returns a wrapper of the node at the provided index of the current wrapper.

.first() => ShallowWrapper

Returns a wrapper of the first node of the current wrapper.

.last() => ShallowWrapper

Returns a wrapper of the last node of the current wrapper.

.state([key]) => Any

Returns the state of the root component.

.context([key]) => Any

Returns the context of the root component.

.props() => Object

Returns the props of the current node.

.prop(key) => Any

Returns the named prop of the current node.

.key() => String

Returns the key of the current node.

.invoke(propName)(...args) => Any

Invokes a prop function on the current node and returns the function's return value.

.simulate(event[, data]) => ShallowWrapper

Simulates an event on the current node.

.setState(nextState) => ShallowWrapper

Manually sets state of the root component.

.setProps(nextProps[, callback]) => ShallowWrapper

Manually sets props of the root component.

.setContext(context) => ShallowWrapper

Manually sets context of the root component.

.getWrappingComponent() => ShallowWrapper

Returns a wrapper representing the wrappingComponent, if one was passed.

.instance() => ReactComponent

Returns the instance of the root component.

.update() => ShallowWrapper

Syncs the enzyme component tree snapshot with the react component tree.

.debug() => String

Returns a string representation of the current shallow render tree for debugging purposes.

.type() => String|Function|null

Returns the type of the current node of the wrapper.

.name() => String

Returns the name of the current node of the wrapper.

.forEach(fn) => ShallowWrapper

Iterates through each node of the current wrapper and executes the provided function

.map(fn) => Array

Maps the current array of nodes to another array.

.reduce(fn[, initialValue]) => Any

Reduces the current array of nodes to a value

.reduceRight(fn[, initialValue]) => Any

Reduces the current array of nodes to a value, from right to left.

.slice([begin[, end]]) => ShallowWrapper

Returns a new wrapper with a subset of the nodes of the original wrapper, according to the rules of Array#slice.

.tap(intercepter) => Self

Taps into the wrapper method chain. Helpful for debugging.

.some(selector) => Boolean

Returns whether or not any of the nodes in the wrapper match the provided selector.

.someWhere(predicate) => Boolean

Returns whether or not any of the nodes in the wrapper pass the provided predicate function.

.every(selector) => Boolean

Returns whether or not all of the nodes in the wrapper match the provided selector.

.everyWhere(predicate) => Boolean

Returns whether or not all of the nodes in the wrapper pass the provided predicate function.

.dive([options]) => ShallowWrapper

Shallow render the one non-DOM child of the current wrapper, and return a wrapper around the result.