| const passiveEventListenerNames = new Set(['touchstart', 'touchmove', 'wheel', 'mousewheel']) |
| |
| const propIsPassiveTrue = prop => prop.key && prop.key.name === 'passive' && prop.value && prop.value.value === true |
| |
| module.exports = { |
| meta: { |
| docs: {} |
| }, |
| |
| create(context) { |
| return { |
| ['CallExpression[callee.property.name="addEventListener"]']: function(node) { |
| const [name, listener, options] = node.arguments |
| if (!listener) return |
| if (name.type !== 'Literal') return |
| if (!passiveEventListenerNames.has(name.value)) return |
| if (options && options.type === 'ObjectExpression' && options.properties.some(propIsPassiveTrue)) return |
| context.report(node, `High Frequency Events like "${name.value}" should be \`passive: true\``) |
| } |
| } |
| } |
| } |
