npm ERR! missing script: start

npm ERR! A complete log of this run can be found in:
npm ERR!     C:Users..AppDataRoamingnpm-cache_logs2019-04-27T18_02_39_6
60Z-debug.log

{
"name":"javaScript-blockchain",
    "version":"1.0.0",
    "description":"",
    "main":"index.js",
    "scripts": {
        "test":"echo "Error:no test specified" && exit 1",
        "start":"node dev/api.js"
    }
    "author":"Samrat Roy Chowdhuri",
    "license":"ISC",
    "dependencies":{
        "express":"^4.16.3",
        "nodemon":"^1.17.3",
        "sha256":"^0.2.0"
    }
}

0 info it worked if it ends with ok
1 verbose cli [ 'C:\Program Files\nodejs\node.exe',
1 verbose cli   'C:\Program Files\nodejs\node_modules\npm\bin\npm-cli.js',
1 verbose cli   'start' ]
2 info using npm@6.4.1
3 info using node@v10.15.3
4 verbose stack Error: missing script: start
4 verbose stack     at run (C:Program Filesnodejsnode_modulesnpmlibrun-script.js:155:19)
4 verbose stack     at C:Program Filesnodejsnode_modulesnpmlibrun-script.js:63:5
4 verbose stack     at C:Program Filesnodejsnode_modulesnpmnode_modulesread-package-jsonread-json.js:115:5
4 verbose stack     at C:Program Filesnodejsnode_modulesnpmnode_modulesread-package-jsonread-json.js:418:5
4 verbose stack     at checkBinReferences_ (C:Program Filesnodejsnode_modulesnpmnode_modulesread-package-jsonread-json.js:373:45)
4 verbose stack     at final (C:Program Filesnodejsnode_modulesnpmnode_modulesread-package-jsonread-json.js:416:3)
4 verbose stack     at then (C:Program Filesnodejsnode_modulesnpmnode_modulesread-package-jsonread-json.js:160:5)
4 verbose stack     at ReadFileContext.<anonymous> (C:Program Filesnodejsnode_modulesnpmnode_modulesread-package-jsonread-json.js:332:20)
4 verbose stack     at ReadFileContext.callback (C:Program Filesnodejsnode_modulesnpmnode_modulesgraceful-fsgraceful-fs.js:78:16)
4 verbose stack     at FSReqWrap.readFileAfterOpen [as oncomplete] (fs.js:237:13)
5 verbose cwd E:programsblockchain
6 verbose Windows_NT 6.1.7601
7 verbose argv "C:\Program Files\nodejs\node.exe" "C:\Program Files\nodejs\node_modules\npm\bin\npm-cli.js" "start"
8 verbose node v10.15.3
9 verbose npm  v6.4.1
10 error missing script: start
11 verbose exit [ 1, true ]