Meteor error 'cannot declare let twice' when minifying

Question

When minifying meteor app, safari on IOS 10 throws the following error

SyntaxError: Cannot declare a let variable twice: 't'.

I have tried to remove standart-minifier and added abernix:standart-minifier as it was recommended on this comment - they work fine on all the other browsers but on safari ios10 it crashes.

Do you have any recommendations?

Thanks a lot

Edit:

I ended up removing minify packages as it was mentioned here however it definitely not a long-term solution.

Answer 1

The solution to this ios10 safari bug is here

Problem is caused by minify default option

safari10:false

to solve the problem

find these files

/Users/USER/.meteor/packages/abernix_standard-minifier-js/.2.1.0.1v4h096++os+web.browser+web.cordova/plugin.minifyStdJS.os/npm/node_modules/meteor/abernix_minifier-js/node_modules/uglify-es/lib/minify.js

and

/Users/USER/.meteor/packages/abernix_minifier-js/.2.1.0.106pai4++os+web.browser+web.cordova/npm/node_modules/uglify-es/lib/minify.js

then find the following lines and change it as "safari10:true"

if (options.mangle) {
        options.mangle = defaults(options.mangle, {
            cache: null,
            eval: false,
            ie8: false,
            keep_classnames: false,
            keep_fnames: false,
            properties: false,
            reserved: [],
            safari10: true,
            toplevel: false,
        }, true);
    }