javascript演習 6,7日目/３０日

覚えたこと

someとevery

const isAdult = people.some(person => new Date()).getFullYear() - person.year >= 19)

const allAdult = people.every(person => new Date()).getFullYear() - person.year >= 19)

findとfindInex
findIndexとslice

const index = comments.findIndex(item => {
    return item.id === 823423
})
//comments.splice(index,1);これでもいい
const newComments = [
  ...comments.slice(0,index),
  ...comments.slice(index +1 )
];

canvas

const canvas = document.querySelector('#draw');
  const ctx = canvas.getContext('2d');
  canvas.width = window.innerWidth;
  canvas.height = window.innerHeight;
  ctx.strokeStyle = '#bada55';
  ctx.lineJoin = 'round';
  ctx.lineCap = 'round';

マウスで描写

let isDrawing = false;

  function draw(e) {
    if(!isDrawing) return;
    console.log(e)
  }

  canvas.addEventListener('mousemove', draw);
  canvas.addEventListener('mousedown', () => isDrawing = true);
  canvas.addEventListener('mouseup', () => isDrawing = false);
  canvas.addEventListener('mouseout', () => isDrawing = false);

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参考