Getting error while build

[1501bharti]

Every time i try to run npm run-script build : getting error

cross-env REACT_APP_BASENAME=/demo/myproject react-scripts build

Creating an optimized production build...
/home/a/Desktop/Prod/myproject/node_modules/bluebird/js/release/async.js:61
fn = function () { throw arg; };
^

Error: Invalid mapping: {"generated":{"line":318,"column":4},"source":"/home/dataphi/a/Prod/myproject/src/node_modules/shards-ui/src/scss/mixins/_hover.scss","original":{"line":15,"column":-21},"name":null}
at SourceMapGenerator_validateMapping [as _validateMapping] (/h