实用JS工具方法

使用工具集

underscore

lodash

xe-utils

计算文本宽度

function calcFontWidth = (str) {
    const dom = document.createElement('span');
    dom.style = 'display:inline-block;font-size:24px;white-space:no-wrap;';
    dom.textContent = str;
    document.body.appendChild(dom);
    const width = dom.clientWidth;
    document.body.removeChild(dom);
    return width;
}

色值转换

RGB转换为16进制

String.prototype.colorHex = function () {
  // RGB颜色值的正则
  var reg = /^(rgb|RGB)/;
  var color = this;
  if (reg.test(color)) {
    var strHex = "#";
    // 把RGB的3个数值变成数组
    var colorArr = color.replace(/(?:(|)|rgb|RGB)*/g, "").split(",");
    // 转成16进制
    for (var i = 0; i < colorArr.length; i++) {
      var hex = Number(colorArr[i]).toString(16);
      if (hex === "0") {
        hex += hex;
      }
      strHex += hex;
    }
    return strHex;
  } else {
    return String(color);
  }
};

"rgb(255,255,255)".colorHex();  // #ffffff

16进制转换为RGB

String.prototype.colorRgb = function () {
  // 16进制颜色值的正则
  var reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/;
  // 把颜色值变成小写
  var color = this.toLowerCase();
  if (reg.test(color)) {
    // 如果只有三位的值，需变成六位，如：#fff => #ffffff
    if (color.length === 4) {
      var colorNew = "#";
      for (var i = 1; i < 4; i += 1) {
        colorNew += color.slice(i, i + 1).concat(color.slice(i, i + 1));
      }
      color = colorNew;
    }
    // 处理六位的颜色值，转为RGB
    var colorChange = [];
    for (var i = 1; i < 7; i += 2) {
      colorChange.push(parseInt("0x" + color.slice(i, i + 2)));
    }
    return "RGB(" + colorChange.join(",") + ")";
  } else {
    return color;
  }
};

"#fff".colorRgb();  // rgb(255,255,255)
"#ffffff".colorRgb();  // rgb(255,255,255)