在Typescript中访问SASS值（来自variables.scss的$ colors）（Angular2 ionic2） [英] access SASS values ($colors from variables.scss) in Typescript (Angular2 ionic2)

问题描述

在Ionic 2中，我想从文件[my project] \src\theme\variables.scss中访问 $ colors 变量。

In Ionic 2, I would like to access the $colors variables from the file "[my project]\src\theme\variables.scss".

此文件包含：

$colors: (
  primary:    #387ef5,
  secondary:  #32db64,
  danger:     #f53d3d,
  light:      #f4f4f4,
  dark:       #222,
  favorite:   #69BB7B
);

在组件中，我绘制画布。它看起来像是：

In a component, I draw a canvas. It looks like that:

import {Component, Input, ViewChild, ElementRef} from '@angular/core';

@Component({
    selector: 'my-graph',
})
@View({
    template: `<canvas #myGraph class='myGraph'
     [attr.width]='_size'
     [attr.height]='_size'></canvas>`,
})

export class MyGraphDiagram {
    private _size: number;

    // get the element with the #myGraph on it
    @ViewChild("myGraph") myGraph: ElementRef; 

    constructor(){
        this._size = 150;
    }

    ngAfterViewInit() { // wait for the view to init before using the element

      let context: CanvasRenderingContext2D = this.myGraph.nativeElement.getContext("2d");
      // HERE THE COLOR IS DEFINED AND I D LIKE TO ACCESS variable.scss TO DO THAT
      context.fillStyle = 'blue';
      context.fillRect(10, 10, 150, 150);
    }

}

正如人们所见，在此代码中指出形状的颜色是定义的： context.fillStyle ='blue'，我想使用类似 context.fillStyle的东西='[variables.scss OBJECT]。$ colors.primary'。

As one can see, at some point in this code the color of the shape is defined: context.fillStyle = 'blue' , I would like to use instead something like context.fillStyle = '[variables.scss OBJECT].$colors.primary '.

有人知道吗？

推荐答案

不幸的是，没有办法直接从typescript / javascript代码访问SASS变量。但是，我们可以制定解决方法来访问这些变量。

Unfortunately, there is no way to access SASS variable directly from typescript/javascript code. However, we can make a workaround to access those variables.

让我简要介绍一下从打字稿源代码中访问SASS变量的步骤：

Let me describe briefly the steps to access SASS variables from within typescript source code:

创建 ../ providers / sass-helper / sass-helper.component.scss ：

Create ../providers/sass-helper/sass-helper.component.scss:

$prefix: "--"; //Prefix string for custom CSS properties

//Merges a variable name with $prefix
@function custom-property-name($name) {
    @return $prefix + $name;
}

// Defines a custom property
@mixin define-custom-property($name, $value) {
    #{custom-property-name($name)}: $value;
}

body {
    // Append pre-defined colors in $colors:
    @each $name, $value in $colors {
        @include define-custom-property($name, $value);
    }

    // Append SASS variables which are desired to be accesible:
    @include define-custom-property('background-color', $background-color);
}

在这个SCSS文件中，我们只是在体内创建自定义属性 DOM的部分。您应该使用名为 define-custom-property 的 mixin 将要访问的每个SASS变量添加到此SCSS文件中，该变量需要两个参数：变量名和变量值。

In this SCSS file, we simply create custom properties inside the body section of the DOM. You should add each SASS variable that you want to be accessible into this SCSS file by using the mixin called define-custom-property which expects two parameters: variable name and variable value.

例如，我为 $ colors 颜色添加了条目>以及我的 主题/ variables.scss 文件中定义的SASS变量 $ background-color 的条目。您可以根据需要添加任意数量的变量。

As an example, I have added entries for all the colors defined in $colors as well as an entry for the SASS variable $background-color defined in my theme/variables.scss file. You can add as many variables as you wish.

创建 ../ providers / sass-helper / sass-helper.component.ts ：

Create ../providers/sass-helper/sass-helper.component.ts:

import { Component } from '@angular/core';

export const PREFIX = '--';

@Component({
    selector: 'sass-helper',
    template: '<div></div>'
})
export class SassHelperComponent {

    constructor() {

    }

    // Read the custom property of body section with given name:
    readProperty(name: string): string {
        let bodyStyles = window.getComputedStyle(document.body);
        return bodyStyles.getPropertyValue(PREFIX + name);
    }
}

---

2。集成SASS Helper组件

从现在开始，我们可以遵循标准的 Ionic2 框架原则来进行组件集成和使用。

---

2. Integrating SASS Helper Component

From now on, we can follow standard Ionic2 framework principles for component integration and usage.

• 将组件类名称（ SassHelperComponent ）添加到 NgModule 在 app.module.ts



• 将以下HTML代码插入您网页的HTML模板中想要访问这些神奇的变量：

• Add the component class name (SassHelperComponent) into the declarations section of your NgModule in app.module.ts

• Insert the following HTML code into the HTML template of your page from where you want to access those magic variables:

< sass-helper>< / sass-helper>

在页面的TS文件中，您应该在页面类中插入以下行：

In your page's TS file, you should insert the following lines into your page class:

@ViewChild(SassHelperComponent)
private sassHelper: SassHelperComponent;

最后，您可以通过调用子类方法来读取任何SASS变量的值，如下所示：

Finally, you can read the value of any SASS variable by just calling the child class method as follows:

// Read $background-color:
this.sassHelper.readProperty('background-color');

// Read primary:
this.sassHelper.readProperty('primary');

这篇关于在Typescript中访问SASS值（来自variables.scss的$ colors）（Angular2 ionic2）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！