See attached screenshot of the repro

Deleted: 2017-10-20_21-19-04.png 806 KB

	2017-10-20_21-19-04.png 806 KB View Download

Unminified code for the function where the JS error occurs is attached

Seems to be a problem with the ES6 forEach statement

l_oPropNames.forEach(function(i_sPropName) { ... }, this);

However, it does not repro in the unminified version

Deleted: Item.GetDimensions.js 1.4 KB

Item.GetDimensions.js 1.4 KB View Download

Further investigation:

The compiled code looks like: 

    n.prototype.GetDimensions = function() {
        var t, e, o = {}, n = this.m_bResizable || /Resizable|Filler/i.test(this.m_sItemCode), r = /Common\.Structural\.Wall\.Panel$/.test(this.m_sType), i = ["Width", "Height", "Depth"];
        return i.forEach(function(i) {
           // ...
        }, this),
        o
    }

The problem seems to be that the variable "i" is redefined within the closure function and at runtime wipes it before evaluating the forEach operator.

So, it's appears to be a problem with Chrome since it is 2 different scopes and the function declaration shouldn't affect the parent scope prior to execution. It almost looks as if it tried to evaluate the whole function before running it (JIT issue?)

Another observation:

if you change the code from

i = ["Width", "Height", "Depth"];

to

i = new Array("Width", "Height", "Depth");

it resolves the issue

Tested on Chrome Stable #62.0.3202.62 on Windows 10, Mac 10.12.6 and Ubuntu 14.04 and issue is reproduced. However, in Canary #64.0.3248.0 and Dev #63.0.3239.9 issue is not reproduced.

Using the reverse bisect providing the bisect results,

Good Build: 63.0.3215.0 (501821)
Bad Build: 63.0.3214.0 (501490)

You are probably looking for a change made after 501809 (known good), but no later than 501810 (first known bad).

CHANGELOG URL:
https://chromium.googlesource.com/chromium/src/+log/b423745e74dbc212cd2eade952648c166a9b57b5..e599a8176262409568cf32fd7ec2e9f7869c1539
https://chromium.googlesource.com/chromium/src/+/e599a8176262409568cf32fd7ec2e9f7869c1539

Review-URL: https://chromium-review.googlesource.com/666003

From the CL above, assigning the issue to the owner concerned.

@trchen: Could you please look into the issue, pardon me if it has nothing to do with your changes and if possible please assign it to owner concerned.

Thanks

Said CL only updates known test results.

It is likely that repro was not 100% thus the bisect failed. Please has the bisect redone. Thanks!

Unable to provide bisect details as the behavior is inconsistent on different platforms. For the Chrome #63.0.3215.0, it is working as expected on Windows 10 and issue is noticed on Ubuntu 14.04. Attaching screenshot for reference.

Marking this issue as Untriaged, So that the issue gets addressed.

Note: When tried to take bisect using script, script always generated different results.

Thanks.

Deleted: 777067.png 1.7 MB

	777067.png 1.7 MB View Download

Isn't it a duplicate of  issue 777836  ?