Returns a new array containing the first n elements of the input array.
A non-finite n (NaN or Infinity) is treated as 0, floats are
truncated, negative values are clamped to 0, and values greater than the
array length are clamped to the length.
从数组开头截取前 n 个元素。
返回一个新数组，包含输入数组的前 n 个元素。非有限值 n（NaN 或 Infinity）按 0 处理，浮点数会被截断，负数按 0 处理，超过数组长度的值按数组长度处理。
Takes the first n elements of an array.
Returns a new array containing the first
nelements of the input array. A non-finiten(NaNorInfinity) is treated as0, floats are truncated, negative values are clamped to0, and values greater than the array length are clamped to the length.从数组开头截取前 n 个元素。
返回一个新数组，包含输入数组的前
n个元素。非有限值n（NaN或Infinity）按0处理，浮点数会被截断，负数按0处理，超过数组长度的值按数组长度处理。