How to align icon left and text centred in a html button?

Question

How can you have a button with an icon that is aligned left (far left in the button) and the text still centred in the button?

.GoogleSignIn{
    border-radius: 50px;
    padding: 10px;
    text-align: center;
    align-items: center;
    width: 100%;
    height: 42px;
    font-size: 14px;
    font-weight: 500;
    background-color: white;
    border: none;
    color: black;
    margin-bottom: 10px;
    cursor: pointer;
    outline: none;
    display: flex;
    /* justify-content: center; */
}
.GoogleIcon{
    margin: -40px 0px -12px -440%;
}
.GoogleIconContainer{
    align-self: flex-end;
    display: flex;
}

<button className={classes.GoogleSignIn}>
                    <div className = {classes.GoogleIconContainer}>
                        <img src={GoogleIcon} className = {classes.GoogleIcon}/>
                    </div>
                    Sign in with google
</button>

Answer 1

5 lines of CSS code and extra span (For the text). ** Also useful for navbar layout (left logo & center menu).

flex container
-- flex item 1 
-- flex item 2

"The trick": set flex-item-1 margin-right: auto (Now flex-item-2 move to the right edge "push effect").

Next, use one more margin-right: auto for flex-item-2 ("push to the right perfectly center")

snippet

button{
  display: flex;  
  align-items: center;
  justify-content: center;
}
button img{
  margin-right: auto;
  border: 1px solid red;
}

button span{
  border: 1px solid red;
  margin-right: auto;
}

<button style="width: 100%;">
  <img src="https://svgshare.com/i/5vv.svg">
  <span>
    Hello world  
  </span>
</button>

<br>
<button style="width: 200px;">
  <img src="https://svgshare.com/i/5vv.svg">
  <span>
    Hello world  
  </span>
</button>

important To get "perfect V/H align" Do not add any extra top/bottom margin/padding for the content inside the button - icon -or- the text ("Famous" mistake).

important-2 Remove button fixed height (Avoid overflow-y issues). The height of the button declares by content (font-size, image) & padding/border (box-model).

button{
  display: flex;  
  align-items: center;
  justify-content: center;
}
button img{
  margin-right: auto;
  border: 1px solid red;
}

button span{
  border: 1px solid red;
  margin-right: auto;
}

<button style="height: 20px;">
  <img src="https://svgshare.com/i/5vv.svg">
  <span style="font-size: 30px;">
    40px height ==> ovefrlow issues
  </span>
</button>

<br><br><br><br>

<button style="height: 30px; overflow-y: scroll">
  <img src="https://svgshare.com/i/5vv.svg">
  <span style="font-size: 40px;">
    40px height ==> ovefrlow issues
  </span>
</button>

Done :)

Related (Extra reading):

• https://css-tricks.com/how-auto-margins-work-in-flexbox/
• https://www.smashingmagazine.com/2018/08/flexbox-alignment/
• https://scrimba.com/learn/flexbox