function-linear-gradient-no-nonstandard-direction

禁止线性梯度函数使用非标准方向值。

¥Disallow non-standard direction values for linear gradient functions.

.foo { background: linear-gradient(to top, #fff, #000); }
/**                                ↑

 * This (optional) first argument is the "direction" */

有效且标准的方向值是以下之一：

¥A valid and standard direction value is one of the following:

• 一个角度

  ¥an angle

• to 加一个边或角（to top、to bottom、to left、to right；to top right、to right top、to bottom left 等）

  ¥to plus a side-or-corner (to top, to bottom, to left, to right; to top right, to right top, to bottom left, etc.)

一个常见的错误（匹配过时的非标准语法）是仅使用边或角而不使用前面的 to。

¥A common mistake (matching outdated non-standard syntax) is to use just a side-or-corner without the preceding to.

选项

¥Options

true

以下模式被视为问题：

¥The following patterns are considered problems:

.foo { background: linear-gradient(top, #fff, #000); }

.foo { background: linear-gradient(bottom, #fff, #000); }

.foo { background: linear-gradient(left, #fff, #000); }

.foo { background: linear-gradient(45, #fff, #000); }

.foo { background: linear-gradient(to top top, #fff, #000); }

以下模式不被视为问题：

¥The following patterns are not considered problems:

.foo { background: linear-gradient(to top, #fff, #000); }

.foo { background: linear-gradient(to bottom right, #fff, #000); }

.foo { background: linear-gradient(45deg, #fff, #000); }

.foo { background: linear-gradient(1.57rad, #fff, #000); }

/* Direction defaults to "to bottom" */
.foo { background: linear-gradient(#fff, #000); }