md/src/scripts/util.js

import default_theme from './themes/default-theme'
import prettier from 'prettier/standalone'
import prettierMarkdown from 'prettier/parser-markdown'


// 设置自定义颜色
export function setColorWithTemplate(template) {
    return function (color) {
        let custom_theme = JSON.parse(JSON.stringify(template))
        custom_theme.block.h1['border-bottom'] = `2px solid ${color}`
        custom_theme.block.h2['background'] = color
        custom_theme.block.h3['border-left'] = `3px solid ${color}`
        custom_theme.block.h4['color'] = color
        custom_theme.inline.strong['color'] = color
        return custom_theme
    }
}

export const setColorWithCustomTemplate = function setColorWithCustomTemplate(
    template,
    color
) {
    let custom_theme = JSON.parse(JSON.stringify(template))
    custom_theme.block.h1['border-bottom'] = `2px solid ${color}`
    custom_theme.block.h2['background'] = color
    custom_theme.block.h3['border-left'] = `3px solid ${color}`
    custom_theme.block.h4['color'] = color
    custom_theme.inline.strong['color'] = color
    return custom_theme
}

// 设置自定义字体大小
export function setFontSizeWithTemplate(template) {
    return function (fontSize) {
        let custom_theme = JSON.parse(JSON.stringify(template))
        custom_theme.block.h1['font-size'] = `${fontSize * 1.14}px`
        custom_theme.block.h2['font-size'] = `${fontSize * 1.1}px`
        custom_theme.block.h3['font-size'] = `${fontSize}px`
        custom_theme.block.h4['font-size'] = `${fontSize}px`
        return custom_theme
    }
}

export const setColor = setColorWithTemplate(default_theme)
export const setFontSize = setFontSizeWithTemplate(default_theme)

export function customCssWithTemplate(jsonString, color, theme) {
    let custom_theme = JSON.parse(JSON.stringify(theme))
    // block
    custom_theme.block.h1['border-bottom'] = `2px solid ${color}`
    custom_theme.block.h2['background'] = color
    custom_theme.block.h3['border-left'] = `3px solid ${color}`
    custom_theme.block.h4['color'] = color
    custom_theme.inline.strong['color'] = color

    custom_theme.block.h1 = Object.assign(custom_theme.block.h1, jsonString.h1)
    custom_theme.block.h2 = Object.assign(custom_theme.block.h2, jsonString.h2)
    custom_theme.block.h3 = Object.assign(custom_theme.block.h3, jsonString.h3)
    custom_theme.block.h4 = Object.assign(custom_theme.block.h4, jsonString.h4)
    custom_theme.block.p = Object.assign(custom_theme.block.p, jsonString.p)
    custom_theme.block.blockquote = Object.assign(
        custom_theme.block.blockquote,
        jsonString.blockquote
    )
    custom_theme.block.blockquote_p = Object.assign(
        custom_theme.block.blockquote_p,
        jsonString.blockquote_p
    )
    custom_theme.block.image = Object.assign(
        custom_theme.block.image,
        jsonString.image
    )

    // inline
    custom_theme.inline.strong = Object.assign(
        custom_theme.inline.strong,
        jsonString.strong
    )
    custom_theme.inline.codespan = Object.assign(
        custom_theme.inline.codespan,
        jsonString.codespan
    )
    custom_theme.inline.link = Object.assign(
        custom_theme.inline.link,
        jsonString.link
    )
    custom_theme.inline.wx_link = Object.assign(
        custom_theme.inline.wx_link,
        jsonString.wx_link
    )

    return custom_theme
}

/**
 * 将CSS形式的字符串转换为JSON
 *
 * @param {css字符串} css
 */
export function css2json(css) {
    // 移除CSS所有注释
    let open, close;
    while (
        (open = css.indexOf('/*')) !== -1 &&
        (close = css.indexOf('*/')) !== -1
    ) {
        css = css.substring(0, open) + css.substring(close + 2)
    }

    // 初始化返回值
    let json = {}

    while (css.length > 0 && css.indexOf('{') !== -1 && css.indexOf('}') !== -1) {
        // 存储第一个左/右花括号的下标
        const lbracket = css.indexOf('{')
        const rbracket = css.indexOf('}')

        // 第一步：将声明转换为Object，如：
        // `font: 'Times New Roman' 1em; color: #ff0000; margin-top: 1em;`
        //  ==>
        // `{"font": "'Times New Roman' 1em", "color": "#ff0000", "margin-top": "1em"}`

        // 辅助方法：将array转为object
        function toObject(array) {
            let ret = {}
            array.forEach(e => {
                const index = e.indexOf(':')
                const property = e.substring(0, index).trim()
                const value = e.substring(index + 1).trim()
                ret[property] = value
            })
            return ret
        }

        // 切割声明块并移除空白符，然后放入数组中
        let declarations = css
            .substring(lbracket + 1, rbracket)
            .split(';')
            .map(e => e.trim())
            .filter(e => e.length > 0) // 移除所有""空值

        // 转为Object对象
        declarations = toObject(declarations)

        // 第二步：选择器处理，每个选择器会与它对应的声明相关联，如：
        // `h1, p#bar {color: red}`
        // ==>
        // {"h1": {color: red}, "p#bar": {color: red}}

        let selectors = css
            .substring(0, lbracket)
            // 以,切割，并移除空格：`"h1, p#bar, span.foo"` => ["h1", "p#bar", "span.foo"]
            .split(',')
            .map(selector => selector.trim())

        // 迭代赋值
        selectors.forEach(selector => {
            // 若不存在，则先初始化
            if (!json[selector]) json[selector] = {}
            // 赋值到JSON
            Object.keys(declarations).forEach(key => {
                json[selector][key] = declarations[key]
            })
        })

        // 继续下个声明块
        css = css.slice(rbracket + 1).trim()
    }

    // 返回JSON形式的结果串
    return json
}


/**
 * 将编辑器内容保存到 LocalStorage
 * @param {*} editor 
 * @param {*} name 
 */
export function saveEditorContent(editor, name) {
    const content = editor.getValue(0)

    if (content) {
        localStorage.setItem(name, content)
    } else {
        localStorage.removeItem(name)
    }
}

export function isImageIllegal(file) {
    if (!/\.(gif|jpg|jpeg|png|GIF|JPG|PNG)$/.test(file.name)) {
        return '请上传 JPG/PNG/GIF 格式的图片';
    }
    if (file.size > 5 * 1024 * 1024) {
        return '由于公众号限制，图片大小不能超过 5.0M';
    }
    return false;
}

export function formatDoc(content) {
    const doc = prettier.format(content, {
        parser: 'markdown',
        plugins: [prettierMarkdown]
    })
    return doc
}