How to correctly use Vue JS watch with lodash debounce
Your watch should look like this.
watch: { searchStr: _.debounce(function(newVal){ this.checkSearchStr(newVal) }, 100)},This is a bit unusual, however. I don't see why you would want to debounce a watch. Possibly you would rather just debounce the checkSearchStr method.
watch: { searchStr(newVal){ this.checkSearchStr(newVal) }},methods: { checkSearchStr: _.debounce(function(string) { console.log(this.foo) console.log(this.$store.dispatch('someMethod',string)) }, 100)}One other thing I would like to point out; no where in the code is searchStr defined. When you watch a value with Vue, you are watching a data or computed property. As you have currently defined it, the watch on searchStr will never execute.
As @Bert mentioned in comments this scope is local to the function. Therefore, to make this scope to properties in data, change to:
methods: { checkSearchStr: _.debounce((string) => { console.log(this.foo) console.log(this.$store.dispatch('someMethod',string)) }, 100)}