findOne
查找元素功能（选择器），只获取一个元素。
想获取一个数组，请使用 find()。
关键方法
findOne ( condition: number | string | IFindMethod ): UI
通过 id、innerId、className、tag、函数等条件查找元素，只返回一个元素。
归属
UI
示例
通过 id 查找
ts
import { Leafer, Rect } from 'leafer-ui'
const leafer = new Leafer({ view: window })
const rect1 = new Rect({ id: 'block', fill: '#32cd79' })
const rect2 = new Rect({ fill: '#32cd79' })
leafer.add(rect1)
leafer.add(rect2)
console.log(
leafer.findOne('#block') // rect1
)通过 innerId 查找
ts
import { Leafer, Rect } from 'leafer-ui'
const leafer = new Leafer({ view: window })
const rect1 = new Rect({ id: 'block', fill: '#32cd79' })
const rect2 = new Rect({ fill: '#32cd79' })
leafer.add(rect1)
leafer.add(rect2)
console.log(
leafer.findOne(rect2.innerId) // rect2
)通过 className 查找
ts
import { Leafer, Rect } from 'leafer-ui'
const leafer = new Leafer({ view: window })
const rect1 = new Rect({ className: 'menu', fill: '#32cd79' })
const rect2 = new Rect({ className: 'menu', fill: '#32cd79', x: 150 })
const rect3 = new Rect({ fill: '#32cd79', x: 300 })
leafer.add(rect1)
leafer.add(rect2)
leafer.add(rect3)
console.log(
leafer.findOne('.menu') // rect1
)通过 tag 查找
ts
import { Leafer, Rect, Ellipse } from 'leafer-ui'
const leafer = new Leafer({ view: window })
const rect1 = new Rect({ fill: '#32cd79' })
const rect2 = new Rect({ fill: '#32cd79', x: 150 })
const ellipse = new Ellipse({ fill: '#32cd79', x: 300 })
leafer.add(rect1)
leafer.add(rect2)
leafer.add(ellipse)
console.log(
leafer.findOne('Rect') // rect1
)通过 函数 查找
ts
import { Leafer, Rect, Ellipse } from 'leafer-ui'
const leafer = new Leafer({ view: window })
const rect1 = new Rect({ fill: '#32cd79', stroke: 'black' })
const rect2 = new Rect({ fill: '#32cd79', x: 150 })
const ellipse = new Ellipse({ fill: '#32cd79', stroke: 'black', x: 300 })
leafer.add(rect1)
leafer.add(rect2)
leafer.add(ellipse)
console.log(
leafer.findOne(function (item) {
return item.stroke === 'black' ? 1 : 0 // rect1
})
)