iview/src/utils/assist.js

// 判断参数是否是其中之一
export function oneOf (value, validList) {
    for (let i = 0; i < validList.length; i++) {
        if (value === validList[i]) {
            return true;
        }
    }
    return false;
}

export function camelcaseToHyphen (str) {
    return str.replace(/([a-z])([A-Z])/g, '$1-$2').toLowerCase();
}

// For Modal scrollBar hidden
let cached;
export function getScrollBarSize (fresh) {
    if (fresh || cached === undefined) {
        const inner = document.createElement('div');
        inner.style.width = '100%';
        inner.style.height = '200px';

        const outer = document.createElement('div');
        const outerStyle = outer.style;

        outerStyle.position = 'absolute';
        outerStyle.top = 0;
        outerStyle.left = 0;
        outerStyle.pointerEvents = 'none';
        outerStyle.visibility = 'hidden';
        outerStyle.width = '200px';
        outerStyle.height = '150px';
        outerStyle.overflow = 'hidden';

        outer.appendChild(inner);

        document.body.appendChild(outer);

        const widthContained = inner.offsetWidth;
        outer.style.overflow = 'scroll';
        let widthScroll = inner.offsetWidth;

        if (widthContained === widthScroll) {
            widthScroll = outer.clientWidth;
        }

        document.body.removeChild(outer);

        cached = widthContained - widthScroll;
    }
    return cached;
}

// watch DOM change
export const MutationObserver = window.MutationObserver || window.WebKitMutationObserver || window.MozMutationObserver || false;

const SPECIAL_CHARS_REGEXP = /([\:\-\_]+(.))/g;
const MOZ_HACK_REGEXP = /^moz([A-Z])/;

function camelCase(name) {
    return name.replace(SPECIAL_CHARS_REGEXP, function(_, separator, letter, offset) {
        return offset ? letter.toUpperCase() : letter;
    }).replace(MOZ_HACK_REGEXP, 'Moz$1');
}
// getStyle
export function getStyle (element, styleName) {
    if (!element || !styleName) return null;
    styleName = camelCase(styleName);
    if (styleName === 'float') {
        styleName = 'cssFloat';
    }
    try {
        var computed = document.defaultView.getComputedStyle(element, '');
        return element.style[styleName] || computed ? computed[styleName] : null;
    } catch(e) {
        return element.style[styleName];
    }
}