将对象推入数组以进行循环

Question

so i have a problem with some seemingly simple code. i am trying to calculate the points on a slope of 1/2. but all I am getting is the empty array object.

 const canvas = { width: 1200, height: 600 }; const slopeValues = []; for (let i = canvas.height / 2; i < canvas.height / 2; i--) { let obj = {}; obj.x = i; slopeValues.push(obj); } console.log(slopeValues) 

I should also mention that I do have the original code structured in a test suite(mocha). that shouldn't effect it but I'm not sure as I'm new to TDD.

Answer 1

Your for loop condition is off. You set i = height / 2 and set the condition to i < height / 2 . The condition is already false because (i == height / 2) != (i < height)

Try this one instead:

 const canvas = { width: 1200, height: 600 }; const slopeValues = []; for (let i = canvas.height / 2; i >= 0 / 2; i--) { let obj = {}; obj.x = i; slopeValues.push(obj); } console.log(slopeValues) 

Answer 2

您将i初始化为300，然后在i <300时循环通过。第一次尝试运行该循环时，结果为false，因此将忽略for循环中的代码。