If you encounter an error message like this:
Parser Error: Unexpected token 'px' at column 3 in [70px] in ng:///AppModule/MyComponent.html@5:34 ("="let string of strings">
look at the line the error is referring to. It will look similar to this:
<mat-expansion-panel-header [collapsedHeight]="70px">
You have two options of fixing this:
Option 1: Recommended if the value (70px in this case) is always constant.
Remove the brackets from the attribute: [collapsedHeight] to collapsedHeight. The brackets mean that the value shall be interpreted as Javascript and removing them means interpreting the value as attribute. You code should look like this:
<mat-expansion-panel-header collapsedHeight="70px">
Option 2: Force angular to interpret the value (70px in this case) as a string:
Add single quotes before and after the value makes it valid Javascript:
<mat-expansion-panel-header [collapsedHeight]="'70px'">
I recommend to use this option only if you expect the value to be a non-constant javascript expression in the future.